21116544331 has 2 divisors, whose sum is σ = 21116544332. Its totient is φ = 21116544330.

The previous prime is 21116544313. The next prime is 21116544377. The reversal of 21116544331 is 13344561112.

Together with previous prime (21116544313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21116544331 - 2²⁵ = 21082989899 is a prime.

It is a super-2 number, since 2×21116544331² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21116544293 and 21116544302.

It is not a weakly prime, because it can be changed into another prime (21116544931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558272165 + 10558272166.

It is an arithmetic number, because the mean of its divisors is an integer number (10558272166).

Almost surely, 2^21116544331 is an apocalyptic number.

21116544331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116544331 is an equidigital number, since it uses as much as digits as its factorization.

21116544331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 31.

The spelling of 21116544331 in words is "twenty-one billion, one hundred sixteen million, five hundred forty-four thousand, three hundred thirty-one".