18129136821 has 32 divisors (see below), whose sum is σ = 26493350400. Its totient is φ = 10975964160.

The previous prime is 18129136757. The next prime is 18129136849. The reversal of 18129136821 is 12863192181.

It is not a de Polignac number, because 18129136821 - 2⁶ = 18129136757 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18129136871) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3282100 + ... + 3287618.

It is an arithmetic number, because the mean of its divisors is an integer number (827917200).

Almost surely, 2^18129136821 is an apocalyptic number.

It is an amenable number.

18129136821 is a deficient number, since it is larger than the sum of its proper divisors (8364213579).

18129136821 is a wasteful number, since it uses less digits than its factorization.

18129136821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7789.

The product of its digits is 41472, while the sum is 42.

The spelling of 18129136821 in words is "eighteen billion, one hundred twenty-nine million, one hundred thirty-six thousand, eight hundred twenty-one".