91639398400 has 405 divisors, whose sum is σ = 255741159513. Its totient is φ = 32548454400.

The previous prime is 91639398343. The next prime is 91639398401. The reversal of 91639398400 is 489393619.

The square root of 91639398400 is 302720.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 32990183424 + 58649214976 = 181632^2 + 242176^2 .

It is a super-2 number, since 2×91639398400² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91639398401) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2131148779 + ... + 2131148821.

Almost surely, 2^91639398400 is an apocalyptic number.

91639398400 is the 302720-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91639398400

91639398400 is an abundant number, since it is smaller than the sum of its proper divisors (164101761113).

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

91639398400 is an equidigital number, since it uses as much as digits as its factorization.

91639398400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 61 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 52.

The spelling of 91639398400 in words is "ninety-one billion, six hundred thirty-nine million, three hundred ninety-eight thousand, four hundred".