15921315816 has 96 divisors (see below), whose sum is σ = 46626861120. Its totient is φ = 4437918720.

The previous prime is 15921315763. The next prime is 15921315827. The reversal of 15921315816 is 61851312951.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 254220 + ... + 310596.

It is an arithmetic number, because the mean of its divisors is an integer number (485696470).

Almost surely, 2^15921315816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15921315816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23313430560).

15921315816 is an abundant number, since it is smaller than the sum of its proper divisors (30705545304).

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

15921315816 is a wasteful number, since it uses less digits than its factorization.

15921315816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56475 (or 56430 counting only the distinct ones).

The product of its digits is 64800, while the sum is 42.

The spelling of 15921315816 in words is "fifteen billion, nine hundred twenty-one million, three hundred fifteen thousand, eight hundred sixteen".