21112913 has 2 divisors, whose sum is σ = 21112914. Its totient is φ = 21112912.

The previous prime is 21112907. The next prime is 21112951. The reversal of 21112913 is 31921112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14922769 + 6190144 = 3863^2 + 2488^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112913 - 2¹² = 21108817 is a prime.

It is not a weakly prime, because it can be changed into another prime (21112813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556456 + 10556457.

It is an arithmetic number, because the mean of its divisors is an integer number (10556457).

Almost surely, 2^21112913 is an apocalyptic number.

It is an amenable number.

21112913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112913 is an equidigital number, since it uses as much as digits as its factorization.

21112913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 20.

The square root of 21112913 is about 4594.8789973186. The cubic root of 21112913 is about 276.3860077053.

The spelling of 21112913 in words is "twenty-one million, one hundred twelve thousand, nine hundred thirteen".