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185815309969 = 4310632
BaseRepresentation
bin1010110100001101110…
…1001001111010010001
3122202121210021202211101
42231003131021322101
511021022204404334
6221210134544401
716265451034402
oct2550335117221
9582553252741
10185815309969
1171892997683
1230019208101
13146a3686773
148dca28d9a9
154c7800d214
hex2b43749e91

185815309969 has 3 divisors (see below), whose sum is σ = 185815741033. Its totient is φ = 185814878906.

The previous prime is 185815309961. The next prime is 185815309973. The reversal of 185815309969 is 969903518581.

The square root of 185815309969 is 431063.

It is a perfect power (a square), and thus also a powerful number.

185815309969 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 969903518581 = 6131582224337.

It is not a de Polignac number, because 185815309969 - 23 = 185815309961 is a prime.

It is a super-2 number, since 2×1858153099692 (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 185815309969.

It is not an unprimeable number, because it can be changed into a prime (185815309961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 215532 + ... + 646594.

Almost surely, 2185815309969 is an apocalyptic number.

185815309969 is the 431063-rd square number.

185815309969 is the 215532-nd centered octagonal number.

It is an amenable number.

185815309969 is a deficient number, since it is larger than the sum of its proper divisors (431064).

185815309969 is an frugal number, since it uses more digits than its factorization.

185815309969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 862126 (or 431063 counting only the distinct ones).

The product of its (nonzero) digits is 20995200, while the sum is 64.

Multiplying 185815309969 by its sum of digits (64), we get a square (11892179838016 = 34485042).

The spelling of 185815309969 in words is "one hundred eighty-five billion, eight hundred fifteen million, three hundred nine thousand, nine hundred sixty-nine".

Divisors: 1 431063 185815309969