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816077221681 = 2812904189401
BaseRepresentation
bin10111110000000011111…
…11100010111100110001
32220000102211021020000111
423320001333202330301
5101332311232043211
61422522315021321
7112650103634311
oct13700177427461
92800384236014
10816077221681
11295107353367
121121b273a841
135bc56a2c4b7
142b6d9679441
151636498d421
hexbe01fe2f31

816077221681 has 4 divisors (see below), whose sum is σ = 818981411364. Its totient is φ = 813173032000.

The previous prime is 816077221643. The next prime is 816077221693. The reversal of 816077221681 is 186122770618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 318904160656 + 497173061025 = 564716^2 + 705105^2 .

It is a cyclic number.

It is not a de Polignac number, because 816077221681 - 213 = 816077213489 is a prime.

It is a super-2 number, since 2×8160772216812 (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816077221781) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1452094420 + ... + 1452094981.

It is an arithmetic number, because the mean of its divisors is an integer number (204745352841).

Almost surely, 2816077221681 is an apocalyptic number.

It is an amenable number.

816077221681 is a deficient number, since it is larger than the sum of its proper divisors (2904189683).

816077221681 is a wasteful number, since it uses less digits than its factorization.

816077221681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2904189682.

The product of its (nonzero) digits is 451584, while the sum is 49.

The spelling of 816077221681 in words is "eight hundred sixteen billion, seventy-seven million, two hundred twenty-one thousand, six hundred eighty-one".

Divisors: 1 281 2904189401 816077221681