99921615366400 has 81 divisors (see below), whose sum is σ = 247323590148873. Its totient is φ = 39968326272000.

The previous prime is 99921615366359. The next prime is 99921615366403. The reversal of 99921615366400 is 466351612999.

The square root of 99921615366400 is 9996080.

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., 35971781531904 + 63949833834496 = 5997648^2 + 7996864^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99921615366403) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 799623925 + ... + 799748875.

Almost surely, 2^{99921615366400} is an apocalyptic number.

99921615366400 is the 9996080-th square number.

It is an amenable number.

99921615366400 is an abundant number, since it is smaller than the sum of its proper divisors (147401974782473).

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

99921615366400 is an frugal number, since it uses more digits than its factorization.

99921615366400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249928 (or 124958 counting only the distinct ones).

The product of its (nonzero) digits is 18895680, while the sum is 61.

It can be divided in two parts, 9992161 and 5366400, that added together give a square (15358561 = 3919²).

The spelling of 99921615366400 in words is "ninety-nine trillion, nine hundred twenty-one billion, six hundred fifteen million, three hundred sixty-six thousand, four hundred".