21201232218 has 16 divisors (see below), whose sum is σ = 42814140096. Its totient is φ = 6998464800.

The previous prime is 21201232211. The next prime is 21201232223. The reversal of 21201232218 is 81223210212.

It is a super-2 number, since 2×21201232218² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21201232211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17152483 + ... + 17153718.

It is an arithmetic number, because the mean of its divisors is an integer number (2675883756).

Almost surely, 2^21201232218 is an apocalyptic number.

21201232218 is an abundant number, since it is smaller than the sum of its proper divisors (21612907878).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201232218 is a wasteful number, since it uses less digits than its factorization.

21201232218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34306309.

The product of its (nonzero) digits is 768, while the sum is 24.

The spelling of 21201232218 in words is "twenty-one billion, two hundred one million, two hundred thirty-two thousand, two hundred eighteen".