81697590788608 has 160 divisors (see below), whose sum is σ = 175236652015920. Its totient is φ = 37912494735360.

The previous prime is 81697590788563. The next prime is 81697590788621. The reversal of 81697590788608 is 80688709579618.

It can be written as a sum of positive squares in 8 ways, for example, as 4310241036544 + 77387349752064 = 2076112^2 + 8797008^2 .

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, 6138515458 + ... + 6138528766.

Almost surely, 2^{81697590788608} 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 81697590788608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87618326007960).

81697590788608 is an abundant number, since it is smaller than the sum of its proper divisors (93539061227312).

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

81697590788608 is a wasteful number, since it uses less digits than its factorization.

81697590788608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23078 (or 23062 counting only the distinct ones).

The product of its (nonzero) digits is 2926264320, while the sum is 82.

The spelling of 81697590788608 in words is "eighty-one trillion, six hundred ninety-seven billion, five hundred ninety million, seven hundred eighty-eight thousand, six hundred eight".