15971138531 has 4 divisors (see below), whose sum is σ = 15985698552. Its totient is φ = 15956578512.

The previous prime is 15971138489. The next prime is 15971138549. The reversal of 15971138531 is 13583117951.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 15971138531 - 2³⁰ = 14897396707 is a prime.

It is a super-2 number, since 2×15971138531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15971138551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7278365 + ... + 7280558.

It is an arithmetic number, because the mean of its divisors is an integer number (3996424638).

Almost surely, 2^15971138531 is an apocalyptic number.

15971138531 is a deficient number, since it is larger than the sum of its proper divisors (14560021).

15971138531 is a wasteful number, since it uses less digits than its factorization.

15971138531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14560020.

The product of its digits is 113400, while the sum is 44.

The spelling of 15971138531 in words is "fifteen billion, nine hundred seventy-one million, one hundred thirty-eight thousand, five hundred thirty-one".