19664 has 10 divisors (see below), whose sum is σ = 38130. Its totient is φ = 9824.

The previous prime is 19661. The next prime is 19681. The reversal of 19664 is 46691.

It can be written as a sum of positive squares in only one way, i.e., 19600 + 64 = 140^2 + 8^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 599 + ... + 630.

It is an arithmetic number, because the mean of its divisors is an integer number (3813).

2¹⁹⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

19664 is a deficient number, since it is larger than the sum of its proper divisors (18466).

19664 is a wasteful number, since it uses less digits than its factorization.

19664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237 (or 1231 counting only the distinct ones).

The product of its digits is 1296, while the sum is 26.

The square root of 19664 is about 140.2283851437. The cubic root of 19664 is about 26.9913095030.

It can be divided in two parts, 196 and 64, that multiplied together give a square (12544 = 112²).

The spelling of 19664 in words is "nineteen thousand, six hundred sixty-four".