18273920121 has 24 divisors (see below), whose sum is σ = 27553500104. Its totient is φ = 11659023360.

The previous prime is 18273920107. The next prime is 18273920123. The reversal of 18273920121 is 12102937281.

It can be written as a sum of positive squares in 4 ways, for example, as 3159676521 + 15114243600 = 56211^2 + 122940^2 .

It is a de Polignac number, because none of the positive numbers 2^k-18273920121 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18273920123) 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, 429496 + ... + 470121.

Almost surely, 2^18273920121 is an apocalyptic number.

It is an amenable number.

18273920121 is a deficient number, since it is larger than the sum of its proper divisors (9279579983).

18273920121 is a wasteful number, since it uses less digits than its factorization.

18273920121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 899721 (or 899718 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The spelling of 18273920121 in words is "eighteen billion, two hundred seventy-three million, nine hundred twenty thousand, one hundred twenty-one".