15909843681 has 12 divisors (see below), whose sum is σ = 23038776852. Its totient is φ = 10579843296.

The previous prime is 15909843661. The next prime is 15909843727. The reversal of 15909843681 is 18634890951.

15909843681 is a `hidden beast` number, since 1 + 590 + 9 + 8 + 43 + 6 + 8 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12368998656 + 3540845025 = 111216^2 + 59505^2 .

It is not a de Polignac number, because 15909843681 - 2¹⁰ = 15909842657 is a prime.

It is a super-2 number, since 2×15909843681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (15909843641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2222826 + ... + 2229971.

It is an arithmetic number, because the mean of its divisors is an integer number (1919898071).

Almost surely, 2^15909843681 is an apocalyptic number.

It is an amenable number.

15909843681 is a deficient number, since it is larger than the sum of its proper divisors (7128933171).

15909843681 is a wasteful number, since it uses less digits than its factorization.

15909843681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4453200 (or 4453197 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The spelling of 15909843681 in words is "fifteen billion, nine hundred nine million, eight hundred forty-three thousand, six hundred eighty-one".