21115222591 has 2 divisors, whose sum is σ = 21115222592. Its totient is φ = 21115222590.

The previous prime is 21115222573. The next prime is 21115222607. The reversal of 21115222591 is 19522251112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21115222591 - 2¹³ = 21115214399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115222501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557611295 + 10557611296.

It is an arithmetic number, because the mean of its divisors is an integer number (10557611296).

Almost surely, 2^21115222591 is an apocalyptic number.

21115222591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115222591 is an equidigital number, since it uses as much as digits as its factorization.

21115222591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 31.

The spelling of 21115222591 in words is "twenty-one billion, one hundred fifteen million, two hundred twenty-two thousand, five hundred ninety-one".