81566624592 has 80 divisors (see below), whose sum is σ = 236757168000. Its totient is φ = 26883369216.

The previous prime is 81566624527. The next prime is 81566624599. The reversal of 81566624592 is 29542666518.

It is a super-2 number, since 2×81566624592² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81566624599) 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, 1022292 + ... + 1099187.

It is an arithmetic number, because the mean of its divisors is an integer number (2959464600).

Almost surely, 2^81566624592 is an apocalyptic number.

It is an amenable number.

81566624592 is an abundant number, since it is smaller than the sum of its proper divisors (155190543408).

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

81566624592 is a wasteful number, since it uses less digits than its factorization.

81566624592 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121585 (or 2121573 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 54.

The spelling of 81566624592 in words is "eighty-one billion, five hundred sixty-six million, six hundred twenty-four thousand, five hundred ninety-two".