21331022591 has 2 divisors, whose sum is σ = 21331022592. Its totient is φ = 21331022590.

The previous prime is 21331022507. The next prime is 21331022627. The reversal of 21331022591 is 19522013312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21331022591 - 2¹⁸ = 21330760447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21331022501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665511295 + 10665511296.

It is an arithmetic number, because the mean of its divisors is an integer number (10665511296).

Almost surely, 2^21331022591 is an apocalyptic number.

21331022591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331022591 is an equidigital number, since it uses as much as digits as its factorization.

21331022591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The spelling of 21331022591 in words is "twenty-one billion, three hundred thirty-one million, twenty-two thousand, five hundred ninety-one".