21255077813 has 2 divisors, whose sum is σ = 21255077814. Its totient is φ = 21255077812.

The previous prime is 21255077807. The next prime is 21255077819. The reversal of 21255077813 is 31877055212.

It is a balanced prime because it is at equal distance from previous prime (21255077807) and next prime (21255077819).

It can be written as a sum of positive squares in only one way, i.e., 14553527044 + 6701550769 = 120638^2 + 81863^2 .

It is a cyclic number.

It is not a de Polignac number, because 21255077813 - 2⁴ = 21255077797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21255077819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627538906 + 10627538907.

It is an arithmetic number, because the mean of its divisors is an integer number (10627538907).

Almost surely, 2^21255077813 is an apocalyptic number.

It is an amenable number.

21255077813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255077813 is an equidigital number, since it uses as much as digits as its factorization.

21255077813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 117600, while the sum is 41.

The spelling of 21255077813 in words is "twenty-one billion, two hundred fifty-five million, seventy-seven thousand, eight hundred thirteen".