21313991063 has 4 divisors (see below), whose sum is σ = 21441619920. Its totient is φ = 21186362208.

The previous prime is 21313991053. The next prime is 21313991087. The reversal of 21313991063 is 36019931312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21313991063 - 2²⁰ = 21312942487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313991053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63814178 + ... + 63814511.

It is an arithmetic number, because the mean of its divisors is an integer number (5360404980).

Almost surely, 2^21313991063 is an apocalyptic number.

21313991063 is a deficient number, since it is larger than the sum of its proper divisors (127628857).

21313991063 is a wasteful number, since it uses less digits than its factorization.

21313991063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127628856.

The product of its (nonzero) digits is 26244, while the sum is 38.

The spelling of 21313991063 in words is "twenty-one billion, three hundred thirteen million, nine hundred ninety-one thousand, sixty-three".