21555595192613 has 2 divisors, whose sum is σ = 21555595192614. Its totient is φ = 21555595192612.

The previous prime is 21555595192567. The next prime is 21555595192631. The reversal of 21555595192613 is 31629159555512.

Together with next prime (21555595192631) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21260564802724 + 295030389889 = 4610918^2 + 543167^2 .

It is a cyclic number.

It is not a de Polignac number, because 21555595192613 - 2²⁸ = 21555326757157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21555595192013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777797596306 + 10777797596307.

It is an arithmetic number, because the mean of its divisors is an integer number (10777797596307).

Almost surely, 2^{21555595192613} is an apocalyptic number.

It is an amenable number.

21555595192613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21555595192613 is an equidigital number, since it uses as much as digits as its factorization.

21555595192613 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18225000, while the sum is 59.

The spelling of 21555595192613 in words is "twenty-one trillion, five hundred fifty-five billion, five hundred ninety-five million, one hundred ninety-two thousand, six hundred thirteen".