15531344664 has 128 divisors (see below), whose sum is σ = 43891130880. Its totient is φ = 4538419200.

The previous prime is 15531344663. The next prime is 15531344677. The reversal of 15531344664 is 46644313551.

It is a happy number.

It is a super-2 number, since 2×15531344664² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15531344663) 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, 1096749 + ... + 1110819.

It is an arithmetic number, because the mean of its divisors is an integer number (342899460).

Almost surely, 2^15531344664 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 15531344664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21945565440).

15531344664 is an abundant number, since it is smaller than the sum of its proper divisors (28359786216).

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

15531344664 is a wasteful number, since it uses less digits than its factorization.

15531344664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14241 (or 14237 counting only the distinct ones).

The product of its digits is 518400, while the sum is 42.

The spelling of 15531344664 in words is "fifteen billion, five hundred thirty-one million, three hundred forty-four thousand, six hundred sixty-four".