18581779225 has 27 divisors (see below), whose sum is σ = 23328042717. Its totient is φ = 14682761280.

The previous prime is 18581779211. The next prime is 18581779247. The reversal of 18581779225 is 52297718581.

It is a happy number.

The square root of 18581779225 is 136315.

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

It can be written as a sum of positive squares in 4 ways, for example, as 54213769 + 18527565456 = 7363^2 + 136116^2 .

It is not a de Polignac number, because 18581779225 - 2⁵ = 18581779193 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 93375676 + ... + 93375874.

Almost surely, 2^18581779225 is an apocalyptic number.

18581779225 is the 136315-th square number.

18581779225 is the 68158-th centered octagonal number.

It is an amenable number.

18581779225 is a deficient number, since it is larger than the sum of its proper divisors (4746263492).

18581779225 is an frugal number, since it uses more digits than its factorization.

18581779225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682 (or 341 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 55.

The spelling of 18581779225 in words is "eighteen billion, five hundred eighty-one million, seven hundred seventy-nine thousand, two hundred twenty-five".