21664482 has 64 divisors (see below), whose sum is σ = 53028864. Its totient is φ = 5765760.

The previous prime is 21664471. The next prime is 21664483. The reversal of 21664482 is 28446612.

It is not an unprimeable number, because it can be changed into a prime (21664483) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 39333 + ... + 39879.

It is an arithmetic number, because the mean of its divisors is an integer number (828576).

Almost surely, 2^21664482 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21664482, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26514432).

21664482 is an abundant number, since it is smaller than the sum of its proper divisors (31364382).

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

21664482 is a wasteful number, since it uses less digits than its factorization.

21664482 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623.

The product of its digits is 18432, while the sum is 33.

The square root of 21664482 is about 4654.5120044963. The cubic root of 21664482 is about 278.7721833445.

The spelling of 21664482 in words is "twenty-one million, six hundred sixty-four thousand, four hundred eighty-two".