20639936 has 28 divisors (see below), whose sum is σ = 41102280. Its totient is φ = 10283520.

The previous prime is 20639923. The next prime is 20639939. The reversal of 20639936 is 63993602.

It is a self number, because there is not a number n which added to its sum of digits gives 20639936.

It is not an unprimeable number, because it can be changed into a prime (20639939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33035 + ... + 33653.

Almost surely, 2^20639936 is an apocalyptic number.

It is an amenable number.

20639936 is a deficient number, since it is larger than the sum of its proper divisors (20462344).

20639936 is an equidigital number, since it uses as much as digits as its factorization.

20639936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1152 (or 1142 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 38.

The square root of 20639936 is about 4543.1196330275. The cubic root of 20639936 is about 274.3065104933.

The spelling of 20639936 in words is "twenty million, six hundred thirty-nine thousand, nine hundred thirty-six".