21211222231 has 2 divisors, whose sum is σ = 21211222232. Its totient is φ = 21211222230.

The previous prime is 21211222217. The next prime is 21211222391. The reversal of 21211222231 is 13222211212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21211222231 - 2⁷ = 21211222103 is a prime.

It is a super-2 number, since 2×21211222231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21211222199 and 21211222208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211222931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605611115 + 10605611116.

It is an arithmetic number, because the mean of its divisors is an integer number (10605611116).

Almost surely, 2^21211222231 is an apocalyptic number.

21211222231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211222231 is an equidigital number, since it uses as much as digits as its factorization.

21211222231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

Adding to 21211222231 its reverse (13222211212), we get a palindrome (34433433443).

The spelling of 21211222231 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred thirty-one".