21253686168 has 64 divisors (see below), whose sum is σ = 62423424000. Its totient is φ = 5945086080.

The previous prime is 21253686119. The next prime is 21253686169. The reversal of 21253686168 is 86168635212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253686169) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3092968 + ... + 3099831.

It is an arithmetic number, because the mean of its divisors is an integer number (975366000).

Almost surely, 2^21253686168 is an apocalyptic number.

It is an amenable number.

21253686168 is an abundant number, since it is smaller than the sum of its proper divisors (41169737832).

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

21253686168 is a wasteful number, since it uses less digits than its factorization.

21253686168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6192832 (or 6192828 counting only the distinct ones).

The product of its digits is 829440, while the sum is 48.

The spelling of 21253686168 in words is "twenty-one billion, two hundred fifty-three million, six hundred eighty-six thousand, one hundred sixty-eight".