21100164 has 12 divisors (see below), whose sum is σ = 49233744. Its totient is φ = 7033384.

The previous prime is 21100159. The next prime is 21100171. The reversal of 21100164 is 46100112.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 879162 + ... + 879185.

It is an arithmetic number, because the mean of its divisors is an integer number (4102812).

Almost surely, 2^21100164 is an apocalyptic number.

It is an amenable number.

21100164 is an abundant number, since it is smaller than the sum of its proper divisors (28133580).

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

21100164 is a wasteful number, since it uses less digits than its factorization.

21100164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1758354 (or 1758352 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21100164 is about 4593.4914825218. The cubic root of 21100164 is about 276.3303647488.

Adding to 21100164 its reverse (46100112), we get a palindrome (67200276).

The spelling of 21100164 in words is "twenty-one million, one hundred thousand, one hundred sixty-four".