18485393521 has 9 divisors (see below), whose sum is σ = 21504524121. Its totient is φ = 15843807252.

The previous prime is 18485393519. The next prime is 18485393533. The reversal of 18485393521 is 12539358481.

The square root of 18485393521 is 135961.

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

It is not a de Polignac number, because 18485393521 - 2¹ = 18485393519 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18485393501) 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, 942016 + ... + 961438.

It is an arithmetic number, because the mean of its divisors is an integer number (2389391569).

Almost surely, 2^18485393521 is an apocalyptic number.

18485393521 is the 135961-st square number.

18485393521 is the 67981-st centered octagonal number.

It is an amenable number.

18485393521 is a deficient number, since it is larger than the sum of its proper divisors (3019130600).

18485393521 is an frugal number, since it uses more digits than its factorization.

18485393521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38860 (or 19430 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 49.

Multiplying 18485393521 by its sum of digits (49), we get a square (905784282529 = 951727²).

18485393521 divided by its sum of digits (49) gives a square (377252929 = 19423²).

The spelling of 18485393521 in words is "eighteen billion, four hundred eighty-five million, three hundred ninety-three thousand, five hundred twenty-one".