21036253806 has 12 divisors (see below), whose sum is σ = 45578549952. Its totient is φ = 7012084596.

The previous prime is 21036253793. The next prime is 21036253817. The reversal of 21036253806 is 60835263012.

It is a happy number.

21036253806 is a `hidden beast` number, since 21 + 0 + 3 + 625 + 3 + 8 + 0 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 584340366 + ... + 584340401.

It is an arithmetic number, because the mean of its divisors is an integer number (3798212496).

Almost surely, 2^21036253806 is an apocalyptic number.

21036253806 is an abundant number, since it is smaller than the sum of its proper divisors (24542296146).

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

21036253806 is a wasteful number, since it uses less digits than its factorization.

21036253806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1168680775 (or 1168680772 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 21036253806 in words is "twenty-one billion, thirty-six million, two hundred fifty-three thousand, eight hundred six".