21397885839 has 24 divisors (see below), whose sum is σ = 35701288272. Its totient is φ = 12205566720.

The previous prime is 21397885837. The next prime is 21397885841. The reversal of 21397885839 is 93858879312.

It is an interprime number because it is at equal distance from previous prime (21397885837) and next prime (21397885841).

It is not a de Polignac number, because 21397885839 - 2¹ = 21397885837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21397885837) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6355384 + ... + 6358749.

It is an arithmetic number, because the mean of its divisors is an integer number (1487553678).

Almost surely, 2^21397885839 is an apocalyptic number.

21397885839 is a deficient number, since it is larger than the sum of its proper divisors (14303402433).

21397885839 is a wasteful number, since it uses less digits than its factorization.

21397885839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12714167 (or 12714164 counting only the distinct ones).

The product of its digits is 26127360, while the sum is 63.

The spelling of 21397885839 in words is "twenty-one billion, three hundred ninety-seven million, eight hundred eighty-five thousand, eight hundred thirty-nine".