21211112231 has 2 divisors, whose sum is σ = 21211112232. Its totient is φ = 21211112230.

The previous prime is 21211112207. The next prime is 21211112257. The reversal of 21211112231 is 13221111212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21211112231 - 2¹⁴ = 21211095847 is a prime.

It is a super-2 number, since 2×21211112231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211112201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605556115 + 10605556116.

It is an arithmetic number, because the mean of its divisors is an integer number (10605556116).

Almost surely, 2^21211112231 is an apocalyptic number.

21211112231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211112231 is an equidigital number, since it uses as much as digits as its factorization.

21211112231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48, while the sum is 17.

Adding to 21211112231 its reverse (13221111212), we get a palindrome (34432223443).

The spelling of 21211112231 in words is "twenty-one billion, two hundred eleven million, one hundred twelve thousand, two hundred thirty-one".