21540258756 has 81 divisors (see below), whose sum is σ = 55494616359. Its totient is φ = 7044768000.

The previous prime is 21540258749. The next prime is 21540258763. The reversal of 21540258756 is 65785204512.

The square root of 21540258756 is 146766.

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

21540258756 is a `hidden beast` number, since 2 + 1 + 540 + 2 + 58 + 7 + 56 = 666.

It is an interprime number because it is at equal distance from previous prime (21540258749) and next prime (21540258763).

It can be written as a sum of positive squares in 4 ways, for example, as 142420356 + 21397838400 = 11934^2 + 146280^2 .

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, 53716156 + ... + 53716556.

Almost surely, 2^21540258756 is an apocalyptic number.

21540258756 is the 146766-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21540258756

21540258756 is an abundant number, since it is smaller than the sum of its proper divisors (33954357603).

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

21540258756 is an equidigital number, since it uses as much as digits as its factorization.

21540258756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 934 (or 467 counting only the distinct ones).

The product of its (nonzero) digits is 672000, while the sum is 45.

The spelling of 21540258756 in words is "twenty-one billion, five hundred forty million, two hundred fifty-eight thousand, seven hundred fifty-six".