17921664 has 96 divisors (see below), whose sum is σ = 52827840. Its totient is φ = 5829120.

The previous prime is 17921647. The next prime is 17921677. The reversal of 17921664 is 46612971.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53979 + ... + 54309.

It is an arithmetic number, because the mean of its divisors is an integer number (550290).

Almost surely, 2^17921664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 17921664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26413920).

17921664 is an abundant number, since it is smaller than the sum of its proper divisors (34906176).

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

17921664 is a wasteful number, since it uses less digits than its factorization.

17921664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 383 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 17921664 is about 4233.3986346670. The cubic root of 17921664 is about 261.6934043476.

The spelling of 17921664 in words is "seventeen million, nine hundred twenty-one thousand, six hundred sixty-four".