18261812091 has 32 divisors (see below), whose sum is σ = 25451435520. Its totient is φ = 11637561600.

The previous prime is 18261812089. The next prime is 18261812099. The reversal of 18261812091 is 19021816281.

It is not a de Polignac number, because 18261812091 - 2¹ = 18261812089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18261812099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1417065 + ... + 1429893.

It is an arithmetic number, because the mean of its divisors is an integer number (795357360).

Almost surely, 2^18261812091 is an apocalyptic number.

18261812091 is a deficient number, since it is larger than the sum of its proper divisors (7189623429).

18261812091 is a wasteful number, since it uses less digits than its factorization.

18261812091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13107.

The product of its (nonzero) digits is 13824, while the sum is 39.

The spelling of 18261812091 in words is "eighteen billion, two hundred sixty-one million, eight hundred twelve thousand, ninety-one".