18721525365 has 24 divisors (see below), whose sum is σ = 32454040320. Its totient is φ = 9983768544.

The previous prime is 18721525357. The next prime is 18721525367. The reversal of 18721525365 is 56352512781.

18721525365 is a `hidden beast` number, since 187 + 215 + 253 + 6 + 5 = 666.

It is not a de Polignac number, because 18721525365 - 2³ = 18721525357 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 18721525365.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18721525367) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 622464 + ... + 651846.

It is an arithmetic number, because the mean of its divisors is an integer number (1352251680).

Almost surely, 2^18721525365 is an apocalyptic number.

18721525365 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18721525365 is a deficient number, since it is larger than the sum of its proper divisors (13732514955).

18721525365 is a wasteful number, since it uses less digits than its factorization.

18721525365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43553 (or 43550 counting only the distinct ones).

The product of its digits is 504000, while the sum is 45.

The spelling of 18721525365 in words is "eighteen billion, seven hundred twenty-one million, five hundred twenty-five thousand, three hundred sixty-five".