21120212231 has 4 divisors (see below), whose sum is σ = 22038482352. Its totient is φ = 20201942112.

The previous prime is 21120212189. The next prime is 21120212237. The reversal of 21120212231 is 13221202112.

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 21120212231 - 2¹⁰ = 21120211207 is a prime.

It is a super-2 number, since 2×21120212231² (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 (21120212237) 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, 459135026 + ... + 459135071.

It is an arithmetic number, because the mean of its divisors is an integer number (5509620588).

Almost surely, 2^21120212231 is an apocalyptic number.

21120212231 is a deficient number, since it is larger than the sum of its proper divisors (918270121).

21120212231 is an equidigital number, since it uses as much as digits as its factorization.

21120212231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918270120.

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

Adding to 21120212231 its reverse (13221202112), we get a palindrome (34341414343).

The spelling of 21120212231 in words is "twenty-one billion, one hundred twenty million, two hundred twelve thousand, two hundred thirty-one".