81615827888 has 80 divisors (see below), whose sum is σ = 188661305856. Its totient is φ = 33442675200.

The previous prime is 81615827873. The next prime is 81615827947. The reversal of 81615827888 is 88872851618.

It is a super-2 number, since 2×81615827888² (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 81615827888.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7338620 + ... + 7349732.

Almost surely, 2^81615827888 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 81615827888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94330652928).

81615827888 is an abundant number, since it is smaller than the sum of its proper divisors (107045477968).

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

81615827888 is a wasteful number, since it uses less digits than its factorization.

81615827888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14002 (or 13996 counting only the distinct ones).

The product of its digits is 13762560, while the sum is 62.

The spelling of 81615827888 in words is "eighty-one billion, six hundred fifteen million, eight hundred twenty-seven thousand, eight hundred eighty-eight".