90399721536 has 42 divisors (see below), whose sum is σ = 259114481262. Its totient is φ = 30133240320.

The previous prime is 90399721523. The next prime is 90399721541. The reversal of 90399721536 is 63512799309.

It is a happy number.

90399721536 is a `hidden beast` number, since 9 + 0 + 39 + 9 + 72 + 1 + 536 = 666.

It can be written as a sum of positive squares in only one way, i.e., 71481369600 + 18918351936 = 267360^2 + 137544^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 78471405 + ... + 78472556.

It is an arithmetic number, because the mean of its divisors is an integer number (6169392411).

Almost surely, 2^90399721536 is an apocalyptic number.

90399721536 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

90399721536 is an abundant number, since it is smaller than the sum of its proper divisors (168714759726).

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

90399721536 is a wasteful number, since it uses less digits than its factorization.

90399721536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156943979 (or 156943966 counting only the distinct ones).

The product of its (nonzero) digits is 2755620, while the sum is 54.

The spelling of 90399721536 in words is "ninety billion, three hundred ninety-nine million, seven hundred twenty-one thousand, five hundred thirty-six".