81657152031 has 16 divisors (see below), whose sum is σ = 134001480704. Its totient is φ = 43071904224.

The previous prime is 81657152029. The next prime is 81657152041. The reversal of 81657152031 is 13025175618.

It is not a de Polignac number, because 81657152031 - 2¹ = 81657152029 is a prime.

It is a super-2 number, since 2×81657152031² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81657152041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149554951 + ... + 149555496.

It is an arithmetic number, because the mean of its divisors is an integer number (8375092544).

Almost surely, 2^81657152031 is an apocalyptic number.

81657152031 is a deficient number, since it is larger than the sum of its proper divisors (52344328673).

81657152031 is a wasteful number, since it uses less digits than its factorization.

81657152031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299110470.

The product of its (nonzero) digits is 50400, while the sum is 39.

The spelling of 81657152031 in words is "eighty-one billion, six hundred fifty-seven million, one hundred fifty-two thousand, thirty-one".