21112220231 has 4 divisors (see below), whose sum is σ = 21458322264. Its totient is φ = 20766118200.

The previous prime is 21112220209. The next prime is 21112220243. The reversal of 21112220231 is 13202221112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21112220231 - 2¹⁰ = 21112219207 is a prime.

It is a super-2 number, since 2×21112220231² (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 (21112220251) 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, 173050925 + ... + 173051046.

It is an arithmetic number, because the mean of its divisors is an integer number (5364580566).

Almost surely, 2^21112220231 is an apocalyptic number.

21112220231 is a deficient number, since it is larger than the sum of its proper divisors (346102033).

21112220231 is an equidigital number, since it uses as much as digits as its factorization.

21112220231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346102032.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21112220231 its reverse (13202221112), we get a palindrome (34314441343).

The spelling of 21112220231 in words is "twenty-one billion, one hundred twelve million, two hundred twenty thousand, two hundred thirty-one".