18521994945 has 16 divisors (see below), whose sum is σ = 29650777920. Its totient is φ = 9873201984.

The previous prime is 18521994937. The next prime is 18521994961. The reversal of 18521994945 is 54949912581.

It is not a de Polignac number, because 18521994945 - 2³ = 18521994937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 295150 + ... + 352359.

It is an arithmetic number, because the mean of its divisors is an integer number (1853173620).

Almost surely, 2^18521994945 is an apocalyptic number.

18521994945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18521994945 is a deficient number, since it is larger than the sum of its proper divisors (11128782975).

18521994945 is a wasteful number, since it uses less digits than its factorization.

18521994945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649424.

The product of its digits is 4665600, while the sum is 57.

The spelling of 18521994945 in words is "eighteen billion, five hundred twenty-one million, nine hundred ninety-four thousand, nine hundred forty-five".