15661665858 has 16 divisors (see below), whose sum is σ = 31348791936. Its totient is φ = 5216311920.

The previous prime is 15661665787. The next prime is 15661665889. The reversal of 15661665858 is 85856616651.

It is a junction number, because it is equal to n+sod(n) for n = 15661665798 and 15661665807.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1052841 + ... + 1067612.

It is an arithmetic number, because the mean of its divisors is an integer number (1959299496).

Almost surely, 2^15661665858 is an apocalyptic number.

15661665858 is an abundant number, since it is smaller than the sum of its proper divisors (15687126078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15661665858 is a wasteful number, since it uses less digits than its factorization.

15661665858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2121689.

The product of its digits is 10368000, while the sum is 57.

The spelling of 15661665858 in words is "fifteen billion, six hundred sixty-one million, six hundred sixty-five thousand, eight hundred fifty-eight".