15981501231 has 32 divisors (see below), whose sum is σ = 23876249600. Its totient is φ = 10564551360.

The previous prime is 15981501209. The next prime is 15981501241. The reversal of 15981501231 is 13210518951.

15981501231 is a `hidden beast` number, since 1 + 59 + 81 + 501 + 23 + 1 = 666.

It is not a de Polignac number, because 15981501231 - 2⁵ = 15981501199 is a prime.

It is a super-2 number, since 2×15981501231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15981501241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3717075 + ... + 3721371.

It is an arithmetic number, because the mean of its divisors is an integer number (746132800).

Almost surely, 2^15981501231 is an apocalyptic number.

15981501231 is a deficient number, since it is larger than the sum of its proper divisors (7894748369).

15981501231 is a wasteful number, since it uses less digits than its factorization.

15981501231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5436 (or 5430 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 36.

The spelling of 15981501231 in words is "fifteen billion, nine hundred eighty-one million, five hundred one thousand, two hundred thirty-one".