81312172752 has 40 divisors (see below), whose sum is σ = 210068416864. Its totient is φ = 27102513024.

The previous prime is 81312172751. The next prime is 81312172759. The reversal of 81312172752 is 25727121318.

It is a super-2 number, since 2×81312172752² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81312172752.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81312172751) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1069803 + ... + 1143285.

Almost surely, 2^81312172752 is an apocalyptic number.

It is an amenable number.

81312172752 is an abundant number, since it is smaller than the sum of its proper divisors (128756244112).

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

81312172752 is a wasteful number, since it uses less digits than its factorization.

81312172752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96547 (or 96541 counting only the distinct ones).

The product of its digits is 47040, while the sum is 39.

The spelling of 81312172752 in words is "eighty-one billion, three hundred twelve million, one hundred seventy-two thousand, seven hundred fifty-two".