20939724 has 72 divisors (see below), whose sum is σ = 57696912. Its totient is φ = 6364800.

The previous prime is 20939719. The next prime is 20939731. The reversal of 20939724 is 42793902.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47047 + ... + 47489.

It is an arithmetic number, because the mean of its divisors is an integer number (801346).

Almost surely, 2^20939724 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20939724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28848456).

20939724 is an abundant number, since it is smaller than the sum of its proper divisors (36757188).

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

20939724 is a wasteful number, since it uses less digits than its factorization.

20939724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567 (or 562 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 20939724 is about 4575.9943181783. The cubic root of 20939724 is about 275.6282013295.

The spelling of 20939724 in words is "twenty million, nine hundred thirty-nine thousand, seven hundred twenty-four".