21164160 has 128 divisors (see below), whose sum is σ = 68837760. Its totient is φ = 5529600.

The previous prime is 21164141. The next prime is 21164183. The reversal of 21164160 is 6146112.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140085 + ... + 140235.

It is an arithmetic number, because the mean of its divisors is an integer number (537795).

Almost surely, 2^21164160 is an apocalyptic number.

21164160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21164160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34418880).

21164160 is an abundant number, since it is smaller than the sum of its proper divisors (47673600).

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

21164160 is a wasteful number, since it uses less digits than its factorization.

21164160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21164160 is about 4600.4521516912. The cubic root of 21164160 is about 276.6094493054.

The spelling of 21164160 in words is "twenty-one million, one hundred sixty-four thousand, one hundred sixty".