21056723712 has 432 divisors, whose sum is σ = 66425748480. Its totient is φ = 6643814400.

The previous prime is 21056723599. The next prime is 21056723729. The reversal of 21056723712 is 21732765012.

21056723712 is a `hidden beast` number, since 2 + 1 + 0 + 567 + 23 + 71 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a super-2 number, since 2×21056723712² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 117635239 + ... + 117635417.

Almost surely, 2^21056723712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21056723712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33212874240).

21056723712 is an abundant number, since it is smaller than the sum of its proper divisors (45369024768).

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

21056723712 is an equidigital number, since it uses as much as digits as its factorization.

21056723712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302 (or 276 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The spelling of 21056723712 in words is "twenty-one billion, fifty-six million, seven hundred twenty-three thousand, seven hundred twelve".