18943393225 has 9 divisors (see below), whose sum is σ = 23490660967. Its totient is φ = 15154164040.

The previous prime is 18943393223. The next prime is 18943393229. The reversal of 18943393225 is 52239334981.

The square root of 18943393225 is 137635.

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

It can be written as a sum of positive squares in only one way, i.e., 6819621561 + 12123771664 = 82581^2 + 110108^2 .

It is not a de Polignac number, because 18943393225 - 2¹ = 18943393223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18943393223) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 674412 + ... + 701938.

Almost surely, 2^18943393225 is an apocalyptic number.

18943393225 is the 137635-th square number.

18943393225 is the 68818-th centered octagonal number.

It is an amenable number.

18943393225 is a deficient number, since it is larger than the sum of its proper divisors (4547267742).

18943393225 is an frugal number, since it uses more digits than its factorization.

18943393225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55064 (or 27532 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 49.

Multiplying 18943393225 by its sum of digits (49), we get a square (928226268025 = 963445²).

The spelling of 18943393225 in words is "eighteen billion, nine hundred forty-three million, three hundred ninety-three thousand, two hundred twenty-five".