21921207068591 has 2 divisors, whose sum is σ = 21921207068592. Its totient is φ = 21921207068590.

The previous prime is 21921207068587. The next prime is 21921207068611. The reversal of 21921207068591 is 19586070212912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21921207068591 - 2² = 21921207068587 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21921207068521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10960603534295 + 10960603534296.

It is an arithmetic number, because the mean of its divisors is an integer number (10960603534296).

Almost surely, 2^{21921207068591} is an apocalyptic number.

21921207068591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21921207068591 is an equidigital number, since it uses as much as digits as its factorization.

21921207068591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The spelling of 21921207068591 in words is "twenty-one trillion, nine hundred twenty-one billion, two hundred seven million, sixty-eight thousand, five hundred ninety-one".