21013056 has 63 divisors (see below), whose sum is σ = 60547123. Its totient is φ = 6967680.

The previous prime is 21013049. The next prime is 21013061. The reversal of 21013056 is 65031012.

The square root of 21013056 is 4584.

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

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 109921 + ... + 110111.

Almost surely, 2^21013056 is an apocalyptic number.

21013056 is the 4584-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21013056

21013056 is an abundant number, since it is smaller than the sum of its proper divisors (39534067).

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

21013056 is an equidigital number, since it uses as much as digits as its factorization.

21013056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The cubic root of 21013056 is about 275.9495812124.

Adding to 21013056 its reverse (65031012), we get a palindrome (86044068).

The spelling of 21013056 in words is "twenty-one million, thirteen thousand, fifty-six".