20638812 has 12 divisors (see below), whose sum is σ = 48157256. Its totient is φ = 6879600.

The previous prime is 20638811. The next prime is 20638819. The reversal of 20638812 is 21883602.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 20638812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20638811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 859939 + ... + 859962.

Almost surely, 2^20638812 is an apocalyptic number.

It is an amenable number.

20638812 is an abundant number, since it is smaller than the sum of its proper divisors (27518444).

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

20638812 is a wasteful number, since it uses less digits than its factorization.

20638812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719908 (or 1719906 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 20638812 is about 4542.9959277992. The cubic root of 20638812 is about 274.3015310509.

The spelling of 20638812 in words is "twenty million, six hundred thirty-eight thousand, eight hundred twelve".