21920758506 has 12 divisors (see below), whose sum is σ = 47494976802. Its totient is φ = 7306919496.

The previous prime is 21920758493. The next prime is 21920758523. The reversal of 21920758506 is 60585702912.

21920758506 is a `hidden beast` number, since 2 + 1 + 92 + 0 + 7 + 58 + 506 = 666.

It can be written as a sum of positive squares in only one way, i.e., 20776627881 + 1144130625 = 144141^2 + 33825^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 608909941 + ... + 608909976.

Almost surely, 2^21920758506 is an apocalyptic number.

21920758506 is an abundant number, since it is smaller than the sum of its proper divisors (25574218296).

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

21920758506 is a wasteful number, since it uses less digits than its factorization.

21920758506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1217819925 (or 1217819922 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The spelling of 21920758506 in words is "twenty-one billion, nine hundred twenty million, seven hundred fifty-eight thousand, five hundred six".