19664816 has 20 divisors (see below), whose sum is σ = 39757872. Its totient is φ = 9404736.

The previous prime is 19664779. The next prime is 19664833. The reversal of 19664816 is 61846691.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 26351 + ... + 27086.

Almost surely, 2^19664816 is an apocalyptic number.

19664816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19664816 is an abundant number, since it is smaller than the sum of its proper divisors (20093056).

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

19664816 is a wasteful number, since it uses less digits than its factorization.

19664816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53468 (or 53462 counting only the distinct ones).

The product of its digits is 62208, while the sum is 41.

The square root of 19664816 is about 4434.5029033703. The cubic root of 19664816 is about 269.9168285204.

The spelling of 19664816 in words is "nineteen million, six hundred sixty-four thousand, eight hundred sixteen".