21320111291 has 2 divisors, whose sum is σ = 21320111292. Its totient is φ = 21320111290.

The previous prime is 21320111273. The next prime is 21320111363. The reversal of 21320111291 is 19211102312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21320111291 - 2⁶ = 21320111227 is a prime.

It is not a weakly prime, because it can be changed into another prime (21320141291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660055645 + 10660055646.

It is an arithmetic number, because the mean of its divisors is an integer number (10660055646).

Almost surely, 2^21320111291 is an apocalyptic number.

21320111291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320111291 is an equidigital number, since it uses as much as digits as its factorization.

21320111291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 23.

The spelling of 21320111291 in words is "twenty-one billion, three hundred twenty million, one hundred eleven thousand, two hundred ninety-one".