21255427597 has 2 divisors, whose sum is σ = 21255427598. Its totient is φ = 21255427596.

The previous prime is 21255427519. The next prime is 21255427601. The reversal of 21255427597 is 79572455212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16788644041 + 4466783556 = 129571^2 + 66834^2 .

It is a cyclic number.

It is not a de Polignac number, because 21255427597 - 2¹⁹ = 21254903309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21255427597.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21655427597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627713798 + 10627713799.

It is an arithmetic number, because the mean of its divisors is an integer number (10627713799).

Almost surely, 2^21255427597 is an apocalyptic number.

It is an amenable number.

21255427597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255427597 is an equidigital number, since it uses as much as digits as its factorization.

21255427597 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1764000, while the sum is 49.

The spelling of 21255427597 in words is "twenty-one billion, two hundred fifty-five million, four hundred twenty-seven thousand, five hundred ninety-seven".