15991218507672 has 480 divisors, whose sum is σ = 50145181693200. Its totient is φ = 4741976494080.

The previous prime is 15991218507611. The next prime is 15991218507749. The reversal of 15991218507672 is 27670581219951.

15991218507672 is a `hidden beast` number, since 1 + 59 + 9 + 1 + 2 + 1 + 8 + 507 + 6 + 72 = 666.

It is a super-2 number, since 2×15991218507672² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 455196604 + ... + 455231732.

Almost surely, 2^{15991218507672} is an apocalyptic number.

15991218507672 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15991218507672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25072590846600).

15991218507672 is an abundant number, since it is smaller than the sum of its proper divisors (34153963185528).

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

15991218507672 is a wasteful number, since it uses less digits than its factorization.

15991218507672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35269 (or 35225 counting only the distinct ones).

The product of its (nonzero) digits is 19051200, while the sum is 63.

The spelling of 15991218507672 in words is "fifteen trillion, nine hundred ninety-one billion, two hundred eighteen million, five hundred seven thousand, six hundred seventy-two".