18965421225 has 27 divisors (see below), whose sum is σ = 33972877029. Its totient is φ = 10113789600.

The previous prime is 18965421191. The next prime is 18965421229. The reversal of 18965421225 is 52212456981.

The square root of 18965421225 is 137715.

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

18965421225 is a `hidden beast` number, since 1 + 8 + 96 + 542 + 12 + 2 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 826281 + 18964594944 = 909^2 + 137712^2 .

It is not a de Polignac number, because 18965421225 - 2²⁷ = 18831203497 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (18965421229) 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, 2061135 + ... + 2070315.

Almost surely, 2^18965421225 is an apocalyptic number.

18965421225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18965421225 is the 137715-th square number.

18965421225 is the 68858-th centered octagonal number.

It is an amenable number.

18965421225 is a deficient number, since it is larger than the sum of its proper divisors (15007455804).

18965421225 is an frugal number, since it uses more digits than its factorization.

18965421225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18378 (or 9189 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The spelling of 18965421225 in words is "eighteen billion, nine hundred sixty-five million, four hundred twenty-one thousand, two hundred twenty-five".