20187864 has 48 divisors (see below), whose sum is σ = 54938520. Its totient is φ = 6696960.

The previous prime is 20187833. The next prime is 20187887. The reversal of 20187864 is 46878102.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17959 + ... + 19049.

Almost surely, 2^20187864 is an apocalyptic number.

20187864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20187864 is an abundant number, since it is smaller than the sum of its proper divisors (34750656).

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

20187864 is a wasteful number, since it uses less digits than its factorization.

20187864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1360 (or 1353 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 20187864 is about 4493.0906957238. The cubic root of 20187864 is about 272.2890166112.

The spelling of 20187864 in words is "twenty million, one hundred eighty-seven thousand, eight hundred sixty-four".