21619164 has 24 divisors (see below), whose sum is σ = 57651328. Its totient is φ = 6176880.

The previous prime is 21619159. The next prime is 21619217. The reversal of 21619164 is 46191612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 128602 + ... + 128769.

Almost surely, 2^21619164 is an apocalyptic number.

It is an amenable number.

21619164 is an abundant number, since it is smaller than the sum of its proper divisors (36032164).

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

21619164 is a wasteful number, since it uses less digits than its factorization.

21619164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257385 (or 257383 counting only the distinct ones).

The product of its digits is 2592, while the sum is 30.

The square root of 21619164 is about 4649.6412764857. The cubic root of 21619164 is about 278.5776680860.

It can be divided in two parts, 2161 and 9164, that added together give a triangular number (11325 = T₁₅₀).

The spelling of 21619164 in words is "twenty-one million, six hundred nineteen thousand, one hundred sixty-four".