18521809479 has 24 divisors (see below), whose sum is σ = 27179418240. Its totient is φ = 12152873232.

The previous prime is 18521809447. The next prime is 18521809487. The reversal of 18521809479 is 97490812581.

It is a happy number.

It is not a de Polignac number, because 18521809479 - 2⁵ = 18521809447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18521809429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89812 + ... + 212390.

It is an arithmetic number, because the mean of its divisors is an integer number (1132475760).

Almost surely, 2^18521809479 is an apocalyptic number.

18521809479 is a deficient number, since it is larger than the sum of its proper divisors (8657608761).

18521809479 is a wasteful number, since it uses less digits than its factorization.

18521809479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122851 (or 122848 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 54.

The spelling of 18521809479 in words is "eighteen billion, five hundred twenty-one million, eight hundred nine thousand, four hundred seventy-nine".