18210222221 has 4 divisors (see below), whose sum is σ = 18233361792. Its totient is φ = 18187082652.

The previous prime is 18210222181. The next prime is 18210222259. The reversal of 18210222221 is 12222201281.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18210222221 is a prime.

It is a super-2 number, since 2×18210222221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18210225221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11568605 + ... + 11570178.

It is an arithmetic number, because the mean of its divisors is an integer number (4558340448).

Almost surely, 2^18210222221 is an apocalyptic number.

It is an amenable number.

18210222221 is a deficient number, since it is larger than the sum of its proper divisors (23139571).

18210222221 is an equidigital number, since it uses as much as digits as its factorization.

18210222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23139570.

The product of its (nonzero) digits is 512, while the sum is 23.

The spelling of 18210222221 in words is "eighteen billion, two hundred ten million, two hundred twenty-two thousand, two hundred twenty-one".