21321393724 has 6 divisors (see below), whose sum is σ = 37312439024. Its totient is φ = 10660696860.

The previous prime is 21321393701. The next prime is 21321393787. The reversal of 21321393724 is 42739312312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2665174212 + ... + 2665174219.

Almost surely, 2^21321393724 is an apocalyptic number.

It is an amenable number.

21321393724 is a deficient number, since it is larger than the sum of its proper divisors (15991045300).

21321393724 is a wasteful number, since it uses less digits than its factorization.

21321393724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5330348435 (or 5330348433 counting only the distinct ones).

The product of its digits is 54432, while the sum is 37.

The spelling of 21321393724 in words is "twenty-one billion, three hundred twenty-one million, three hundred ninety-three thousand, seven hundred twenty-four".