21162391200 has 216 divisors, whose sum is σ = 76033250748. Its totient is φ = 5536727040.

The previous prime is 21162391169. The next prime is 21162391213. The reversal of 21162391200 is 219326112.

21162391200 is a `hidden beast` number, since 2 + 11 + 62 + 391 + 200 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 2914704144 + 18247687056 = 53988^2 + 135084^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 353872 + ... + 409328.

Almost surely, 2^21162391200 is an apocalyptic number.

21162391200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21162391200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38016625374).

21162391200 is an abundant number, since it is smaller than the sum of its proper divisors (54870859548).

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

21162391200 is a wasteful number, since it uses less digits than its factorization.

21162391200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55536 (or 55520 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The spelling of 21162391200 in words is "twenty-one billion, one hundred sixty-two million, three hundred ninety-one thousand, two hundred".