15551866161 has 32 divisors (see below), whose sum is σ = 25280277120. Its totient is φ = 9389794752.

The previous prime is 15551866157. The next prime is 15551866171. The reversal of 15551866161 is 16166815551.

15551866161 is a `hidden beast` number, since 1 + 5 + 551 + 86 + 6 + 16 + 1 = 666.

It is not a de Polignac number, because 15551866161 - 2² = 15551866157 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15551866171) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 399391 + ... + 436596.

It is an arithmetic number, because the mean of its divisors is an integer number (790008660).

Almost surely, 2^15551866161 is an apocalyptic number.

It is an amenable number.

15551866161 is a deficient number, since it is larger than the sum of its proper divisors (9728410959).

15551866161 is a wasteful number, since it uses less digits than its factorization.

15551866161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836062 (or 836056 counting only the distinct ones).

The product of its digits is 216000, while the sum is 45.

The spelling of 15551866161 in words is "fifteen billion, five hundred fifty-one million, eight hundred sixty-six thousand, one hundred sixty-one".