20664400 has 60 divisors (see below), whose sum is σ = 52278400. Its totient is φ = 7827840.

The previous prime is 20664379. The next prime is 20664407. The reversal of 20664400 is 446602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20664407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6241 + ... + 8959.

Almost surely, 2^20664400 is an apocalyptic number.

20664400 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 20664400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26139200).

20664400 is an abundant number, since it is smaller than the sum of its proper divisors (31614000).

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

20664400 is a wasteful number, since it uses less digits than its factorization.

20664400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2756 (or 2745 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 20664400 is about 4545.8112587304. The cubic root of 20664400 is about 274.4148439187.

The spelling of 20664400 in words is "twenty million, six hundred sixty-four thousand, four hundred".