21431122018 has 8 divisors (see below), whose sum is σ = 33015512412. Its totient is φ = 10425951216.

The previous prime is 21431121997. The next prime is 21431122021. The reversal of 21431122018 is 81022113412.

It can be written as a sum of positive squares in 2 ways, for example, as 21353100129 + 78021889 = 146127^2 + 8833^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21431121983 and 21431122001.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 144804805 + ... + 144804952.

Almost surely, 2^21431122018 is an apocalyptic number.

21431122018 is a deficient number, since it is larger than the sum of its proper divisors (11584390394).

21431122018 is a wasteful number, since it uses less digits than its factorization.

21431122018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289609796.

The product of its (nonzero) digits is 768, while the sum is 25.

The spelling of 21431122018 in words is "twenty-one billion, four hundred thirty-one million, one hundred twenty-two thousand, eighteen".