18964319521 has 27 divisors (see below), whose sum is σ = 22394037393. Its totient is φ = 16013035080.

The previous prime is 18964319489. The next prime is 18964319531. The reversal of 18964319521 is 12591346981.

It is a happy number.

The square root of 18964319521 is 137711.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 18964319521 - 2⁵ = 18964319489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is not an unprimeable number, because it can be changed into a prime (18964319531) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 99289536 + ... + 99289726.

Almost surely, 2^18964319521 is an apocalyptic number.

18964319521 is the 137711-st square number.

18964319521 is the 68856-th centered octagonal number.

It is an amenable number.

18964319521 is a deficient number, since it is larger than the sum of its proper divisors (3429717872).

18964319521 is an frugal number, since it uses more digits than its factorization.

18964319521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602 (or 301 counting only the distinct ones).

The product of its digits is 466560, while the sum is 49.

Multiplying 18964319521 by its sum of digits (49), we get a square (929251656529 = 963977²).

18964319521 divided by its sum of digits (49) gives a square (387026929 = 19673²).

The spelling of 18964319521 in words is "eighteen billion, nine hundred sixty-four million, three hundred nineteen thousand, five hundred twenty-one".