15968521644 has 24 divisors (see below), whose sum is σ = 37357178880. Its totient is φ = 5308941264.

The previous prime is 15968521643. The next prime is 15968521687. The reversal of 15968521644 is 44612586951.

It is not an unprimeable number, because it can be changed into a prime (15968521643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1732624 + ... + 1741815.

It is an arithmetic number, because the mean of its divisors is an integer number (1556549120).

Almost surely, 2^15968521644 is an apocalyptic number.

It is an amenable number.

15968521644 is an abundant number, since it is smaller than the sum of its proper divisors (21388657236).

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

15968521644 is a wasteful number, since it uses less digits than its factorization.

15968521644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3474829 (or 3474827 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 51.

The spelling of 15968521644 in words is "fifteen billion, nine hundred sixty-eight million, five hundred twenty-one thousand, six hundred forty-four".