21425321591 has 2 divisors, whose sum is σ = 21425321592. Its totient is φ = 21425321590.

The previous prime is 21425321581. The next prime is 21425321647. The reversal of 21425321591 is 19512352412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21425321591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21425321581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712660795 + 10712660796.

It is an arithmetic number, because the mean of its divisors is an integer number (10712660796).

Almost surely, 2^21425321591 is an apocalyptic number.

21425321591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425321591 is an equidigital number, since it uses as much as digits as its factorization.

21425321591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21600, while the sum is 35.

The spelling of 21425321591 in words is "twenty-one billion, four hundred twenty-five million, three hundred twenty-one thousand, five hundred ninety-one".