21216601261231 has 2 divisors, whose sum is σ = 21216601261232. Its totient is φ = 21216601261230.

The previous prime is 21216601261153. The next prime is 21216601261243. The reversal of 21216601261231 is 13216210661212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21216601261231 - 2²⁷ = 21216467043503 is a prime.

It is a super-2 number, since 2×21216601261231² (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 (21216601262231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608300630615 + 10608300630616.

It is an arithmetic number, because the mean of its divisors is an integer number (10608300630616).

Almost surely, 2^{21216601261231} is an apocalyptic number.

21216601261231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216601261231 is an equidigital number, since it uses as much as digits as its factorization.

21216601261231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 34.

The spelling of 21216601261231 in words is "twenty-one trillion, two hundred sixteen billion, six hundred one million, two hundred sixty-one thousand, two hundred thirty-one".