15996522978 has 90 divisors (see below), whose sum is σ = 37902352059. Its totient is φ = 5041874808.

The previous prime is 15996522953. The next prime is 15996523013. The reversal of 15996522978 is 87922569951.

15996522978 is a `hidden beast` number, since 15 + 9 + 9 + 6 + 522 + 97 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 7998261489 + 7998261489 = 89433^2 + 89433^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=89433.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 30585825 + ... + 30586347.

Almost surely, 2^15996522978 is an apocalyptic number.

15996522978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 15996522978

15996522978 is an abundant number, since it is smaller than the sum of its proper divisors (21905829081).

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

15996522978 is an frugal number, since it uses more digits than its factorization.

15996522978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1098 (or 547 counting only the distinct ones).

The product of its digits is 24494400, while the sum is 63.

The spelling of 15996522978 in words is "fifteen billion, nine hundred ninety-six million, five hundred twenty-two thousand, nine hundred seventy-eight".