20724639 has 24 divisors (see below), whose sum is σ = 30682512. Its totient is φ = 12430080.

The previous prime is 20724637. The next prime is 20724653. The reversal of 20724639 is 93642702.

It is not a de Polignac number, because 20724639 - 2¹ = 20724637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20724637) 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, 20289 + ... + 21285.

It is an arithmetic number, because the mean of its divisors is an integer number (1278438).

Almost surely, 2^20724639 is an apocalyptic number.

20724639 is a deficient number, since it is larger than the sum of its proper divisors (9957873).

20724639 is a wasteful number, since it uses less digits than its factorization.

20724639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1054 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 33.

The square root of 20724639 is about 4552.4322070735. The cubic root of 20724639 is about 274.6812350556.

The spelling of 20724639 in words is "twenty million, seven hundred twenty-four thousand, six hundred thirty-nine".