19664400 has 120 divisors (see below), whose sum is σ = 72021184. Its totient is φ = 4492800.

The previous prime is 19664399. The next prime is 19664423. The reversal of 19664400 is 446691.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7230 + ... + 9570.

Almost surely, 2^19664400 is an apocalyptic number.

19664400 is a gapful number since it is divisible by the number (10) 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 19664400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36010592).

19664400 is an abundant number, since it is smaller than the sum of its proper divisors (52356784).

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

19664400 is a wasteful number, since it uses less digits than its factorization.

19664400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369 (or 2358 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 19664400 is about 4434.4559982032. The cubic root of 19664400 is about 269.9149251855.

The spelling of 19664400 in words is "nineteen million, six hundred sixty-four thousand, four hundred".