21255257899 has 2 divisors, whose sum is σ = 21255257900. Its totient is φ = 21255257898.

The previous prime is 21255257893. The next prime is 21255257929. The reversal of 21255257899 is 99875255212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21255257899 - 2²⁵ = 21221703467 is a prime.

It is a super-3 number, since 3×21255257899³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21255257893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627628949 + 10627628950.

It is an arithmetic number, because the mean of its divisors is an integer number (10627628950).

Almost surely, 2^21255257899 is an apocalyptic number.

21255257899 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255257899 is an equidigital number, since it uses as much as digits as its factorization.

21255257899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536000, while the sum is 55.

The spelling of 21255257899 in words is "twenty-one billion, two hundred fifty-five million, two hundred fifty-seven thousand, eight hundred ninety-nine".