21164180 has 24 divisors (see below), whose sum is σ = 44648520. Its totient is φ = 8426880.

The previous prime is 21164141. The next prime is 21164183. The reversal of 21164180 is 8146112.

It can be written as a sum of positive squares in 4 ways, for example, as 5180176 + 15984004 = 2276^2 + 3998^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2270 + ... + 6890.

It is an arithmetic number, because the mean of its divisors is an integer number (1860355).

Almost surely, 2^21164180 is an apocalyptic number.

21164180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21164180 is an abundant number, since it is smaller than the sum of its proper divisors (23484340).

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

21164180 is a wasteful number, since it uses less digits than its factorization.

21164180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4859 (or 4857 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 21164180 is about 4600.4543253900. The cubic root of 21164180 is about 276.6095364368.

The spelling of 21164180 in words is "twenty-one million, one hundred sixty-four thousand, one hundred eighty".