18931664 has 20 divisors (see below), whose sum is σ = 37945860. Its totient is φ = 9139200.

The previous prime is 18931651. The next prime is 18931673. The reversal of 18931664 is 46613981.

It can be written as a sum of positive squares in 2 ways, for example, as 14899600 + 4032064 = 3860^2 + 2008^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19937 + ... + 20864.

It is an arithmetic number, because the mean of its divisors is an integer number (1897293).

Almost surely, 2^18931664 is an apocalyptic number.

It is an amenable number.

18931664 is an abundant number, since it is smaller than the sum of its proper divisors (19014196).

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

18931664 is a wasteful number, since it uses less digits than its factorization.

18931664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40838 (or 40832 counting only the distinct ones).

The product of its digits is 31104, while the sum is 38.

The square root of 18931664 is about 4351.0532058342. The cubic root of 18931664 is about 266.5198719851.

The spelling of 18931664 in words is "eighteen million, nine hundred thirty-one thousand, six hundred sixty-four".