19993664 has 14 divisors (see below), whose sum is σ = 39675054. Its totient is φ = 9996800.

The previous prime is 19993663. The next prime is 19993669. The reversal of 19993664 is 46639991.

It can be written as a sum of positive squares in only one way, i.e., 19009600 + 984064 = 4360^2 + 992^2 .

It is not an unprimeable number, because it can be changed into a prime (19993661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156137 + ... + 156264.

Almost surely, 2^19993664 is an apocalyptic number.

It is an amenable number.

19993664 is a deficient number, since it is larger than the sum of its proper divisors (19681390).

19993664 is an equidigital number, since it uses as much as digits as its factorization.

19993664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312413 (or 312403 counting only the distinct ones).

The product of its digits is 314928, while the sum is 47.

The square root of 19993664 is about 4471.4275125512. The cubic root of 19993664 is about 271.4130943820.

The spelling of 19993664 in words is "nineteen million, nine hundred ninety-three thousand, six hundred sixty-four".