81072317592 has 96 divisors (see below), whose sum is σ = 251362219680. Its totient is φ = 23124372480.

The previous prime is 81072317591. The next prime is 81072317609. The reversal of 81072317592 is 29571327018.

It is a super-2 number, since 2×81072317592² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81072317591) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 163242 + ... + 434502.

It is an arithmetic number, because the mean of its divisors is an integer number (2618356455).

Almost surely, 2^81072317592 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81072317592, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125681109840).

81072317592 is an abundant number, since it is smaller than the sum of its proper divisors (170289902088).

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

81072317592 is a wasteful number, since it uses less digits than its factorization.

81072317592 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271873 (or 271866 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 81072317592 in words is "eighty-one billion, seventy-two million, three hundred seventeen thousand, five hundred ninety-two".