20638956 has 36 divisors (see below), whose sum is σ = 52152072. Its totient is φ = 6349824.

The previous prime is 20638951. The next prime is 20638973. The reversal of 20638956 is 65983602.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20638951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3061 + ... + 7116.

Almost surely, 2^20638956 is an apocalyptic number.

20638956 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20638956 is an abundant number, since it is smaller than the sum of its proper divisors (31513116).

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

20638956 is a wasteful number, since it uses less digits than its factorization.

20638956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10210 (or 10195 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 20638956 is about 4543.0117763440. The cubic root of 20638956 is about 274.3021689967.

The spelling of 20638956 in words is "twenty million, six hundred thirty-eight thousand, nine hundred fifty-six".