21039965894 has 24 divisors (see below), whose sum is σ = 33638325408. Its totient is φ = 9867589200.

The previous prime is 21039965893. The next prime is 21039965897. The reversal of 21039965894 is 49856993012.

It is a Smith number, since the sum of its digits (56) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21039965893) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71342 + ... + 217185.

It is an arithmetic number, because the mean of its divisors is an integer number (1401596892).

Almost surely, 2^21039965894 is an apocalyptic number.

21039965894 is a deficient number, since it is larger than the sum of its proper divisors (12598359514).

21039965894 is a wasteful number, since it uses less digits than its factorization.

21039965894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288668 (or 288649 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 56.

The spelling of 21039965894 in words is "twenty-one billion, thirty-nine million, nine hundred sixty-five thousand, eight hundred ninety-four".