21551426599 has 2 divisors, whose sum is σ = 21551426600. Its totient is φ = 21551426598.

The previous prime is 21551426597. The next prime is 21551426621. The reversal of 21551426599 is 99562415512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21551426599 - 2¹ = 21551426597 is a prime.

Together with 21551426597, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21551426597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775713299 + 10775713300.

It is an arithmetic number, because the mean of its divisors is an integer number (10775713300).

Almost surely, 2^21551426599 is an apocalyptic number.

21551426599 is a deficient number, since it is larger than the sum of its proper divisors (1).

21551426599 is an equidigital number, since it uses as much as digits as its factorization.

21551426599 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972000, while the sum is 49.

The spelling of 21551426599 in words is "twenty-one billion, five hundred fifty-one million, four hundred twenty-six thousand, five hundred ninety-nine".