128161852009 has 3 divisors (see below), whose sum is σ = 128162210007. Its totient is φ = 128161494012.

The previous prime is 128161851991. The next prime is 128161852019. The reversal of 128161852009 is 900258161821.

The square root of 128161852009 is 357997.

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

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.

It can be written as a sum of positive squares in only one way, i.e., 13086216025 + 115075635984 = 114395^2 + 339228^2 .

It is not a de Polignac number, because 128161852009 - 2²³ = 128153463401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128161852019) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 178999 + ... + 536995.

It is an arithmetic number, because the mean of its divisors is an integer number (42720736669).

Almost surely, 2^128161852009 is an apocalyptic number.

128161852009 is the 357997-th square number.

128161852009 is the 178999-th centered octagonal number.

It is an amenable number.

128161852009 is a deficient number, since it is larger than the sum of its proper divisors (357998).

128161852009 is an frugal number, since it uses more digits than its factorization.

128161852009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 715994 (or 357997 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 43.

The spelling of 128161852009 in words is "one hundred twenty-eight billion, one hundred sixty-one million, eight hundred fifty-two thousand, nine".