21221111111231 has 2 divisors, whose sum is σ = 21221111111232. Its totient is φ = 21221111111230.

The previous prime is 21221111111177. The next prime is 21221111111281. The reversal of 21221111111231 is 13211111112212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21221111111231 - 2¹⁸ = 21221110849087 is a prime.

It is a super-2 number, since 2×21221111111231² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221111111281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610555555615 + 10610555555616.

It is an arithmetic number, because the mean of its divisors is an integer number (10610555555616).

Almost surely, 2^{21221111111231} is an apocalyptic number.

21221111111231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221111111231 is an equidigital number, since it uses as much as digits as its factorization.

21221111111231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 20.

Adding to 21221111111231 its reverse (13211111112212), we get a palindrome (34432222223443).

The spelling of 21221111111231 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred eleven thousand, two hundred thirty-one".