21145813056 has 189 divisors, whose sum is σ = 62201621469. Its totient is φ = 6868288512.

The previous prime is 21145813037. The next prime is 21145813079. The reversal of 21145813056 is 65031854112.

The square root of 21145813056 is 145416.

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

21145813056 is a `hidden beast` number, since 21 + 1 + 4 + 581 + 3 + 0 + 56 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12003393600 + 9142419456 = 109560^2 + 95616^2 .

It is a super-3 number, since 3×21145813056³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21145813056.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 254768791 + ... + 254768873.

Almost surely, 2^21145813056 is an apocalyptic number.

21145813056 is the 145416-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21145813056

21145813056 is an abundant number, since it is smaller than the sum of its proper divisors (41055808413).

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

21145813056 is an frugal number, since it uses more digits than its factorization.

21145813056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

Multiplying 21145813056 by its sum of digits (36), we get a square (761249270016 = 872496²).

21145813056 divided by its sum of digits (36) gives a square (587383696 = 24236²).

The spelling of 21145813056 in words is "twenty-one billion, one hundred forty-five million, eight hundred thirteen thousand, fifty-six".