21213110591 has 2 divisors, whose sum is σ = 21213110592. Its totient is φ = 21213110590.

The previous prime is 21213110539. The next prime is 21213110593. The reversal of 21213110591 is 19501131212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213110591 is a prime.

Together with 21213110593, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21213110591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213110593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606555295 + 10606555296.

It is an arithmetic number, because the mean of its divisors is an integer number (10606555296).

Almost surely, 2^21213110591 is an apocalyptic number.

21213110591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213110591 is an equidigital number, since it uses as much as digits as its factorization.

21213110591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 26.

The spelling of 21213110591 in words is "twenty-one billion, two hundred thirteen million, one hundred ten thousand, five hundred ninety-one".