20664320 has 52 divisors (see below), whose sum is σ = 49637460. Its totient is φ = 8257536.

The previous prime is 20664313. The next prime is 20664353. The reversal of 20664320 is 2346602.

It can be written as a sum of positive squares in 2 ways, for example, as 6885376 + 13778944 = 2624^2 + 3712^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19976 + ... + 20984.

Almost surely, 2^20664320 is an apocalyptic number.

20664320 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 20664320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24818730).

20664320 is an abundant number, since it is smaller than the sum of its proper divisors (28973140).

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

20664320 is an equidigital number, since it uses as much as digits as its factorization.

20664320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038 (or 1016 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 20664320 is about 4545.8024594124. The cubic root of 20664320 is about 274.4144897958.

The spelling of 20664320 in words is "twenty million, six hundred sixty-four thousand, three hundred twenty".