15978710664981 has 48 divisors (see below), whose sum is σ = 24053895290880. Its totient is φ = 10599711418800.

The previous prime is 15978710664953. The next prime is 15978710664991. The reversal of 15978710664981 is 18946601787951.

15978710664981 is a `hidden beast` number, since 1 + 5 + 9 + 7 + 8 + 71 + 0 + 66 + 498 + 1 = 666.

15978710664981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 15978710664981 - 2⁵ = 15978710664949 is a prime.

It is a super-2 number, since 2×15978710664981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15978710664991) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 75568756 + ... + 75779906.

It is an arithmetic number, because the mean of its divisors is an integer number (501122818560).

Almost surely, 2^{15978710664981} is an apocalyptic number.

It is an amenable number.

15978710664981 is a deficient number, since it is larger than the sum of its proper divisors (8075184625899).

15978710664981 is a wasteful number, since it uses less digits than its factorization.

15978710664981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212708 (or 212696 counting only the distinct ones).

The product of its (nonzero) digits is 182891520, while the sum is 72.

The spelling of 15978710664981 in words is "fifteen trillion, nine hundred seventy-eight billion, seven hundred ten million, six hundred sixty-four thousand, nine hundred eighty-one".