20878164 has 18 divisors (see below), whose sum is σ = 52775450. Its totient is φ = 6959376.

The previous prime is 20878163. The next prime is 20878171. The reversal of 20878164 is 46187802.

It can be written as a sum of positive squares in only one way, i.e., 13749264 + 7128900 = 3708^2 + 2670^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 579949 = 20878164 / (2 + 0 + 8 + 7 + 8 + 1 + 6 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20878163) 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 5 ways as a sum of consecutive naturals, for example, 289939 + ... + 290010.

Almost surely, 2^20878164 is an apocalyptic number.

It is an amenable number.

20878164 is an abundant number, since it is smaller than the sum of its proper divisors (31897286).

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

20878164 is a wasteful number, since it uses less digits than its factorization.

20878164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 579959 (or 579954 counting only the distinct ones).

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

The square root of 20878164 is about 4569.2629602596. The cubic root of 20878164 is about 275.3578328049.

The spelling of 20878164 in words is "twenty million, eight hundred seventy-eight thousand, one hundred sixty-four".