20639924 has 24 divisors (see below), whose sum is σ = 38911488. Its totient is φ = 9551520.

The previous prime is 20639923. The next prime is 20639939. The reversal of 20639924 is 42993602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 767 + ... + 6470.

It is an arithmetic number, because the mean of its divisors is an integer number (1621312).

Almost surely, 2^20639924 is an apocalyptic number.

It is an amenable number.

20639924 is a deficient number, since it is larger than the sum of its proper divisors (18271564).

20639924 is a wasteful number, since it uses less digits than its factorization.

20639924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7295 (or 7293 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 20639924 is about 4543.1183123489. The cubic root of 20639924 is about 274.3064573330.

The spelling of 20639924 in words is "twenty million, six hundred thirty-nine thousand, nine hundred twenty-four".