21620593653913 has 2 divisors, whose sum is σ = 21620593653914. Its totient is φ = 21620593653912.

The previous prime is 21620593653847. The next prime is 21620593653931. The reversal of 21620593653913 is 31935639502612.

Together with next prime (21620593653931) 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., 17102260998144 + 4518332655769 = 4135488^2 + 2125637^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620593653913 - 2²¹ = 21620591556761 is a prime.

It is not a weakly prime, because it can be changed into another prime (21620593653973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810296826956 + 10810296826957.

It is an arithmetic number, because the mean of its divisors is an integer number (10810296826957).

Almost surely, 2^{21620593653913} is an apocalyptic number.

It is an amenable number.

21620593653913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620593653913 is an equidigital number, since it uses as much as digits as its factorization.

21620593653913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7873200, while the sum is 55.

The spelling of 21620593653913 in words is "twenty-one trillion, six hundred twenty billion, five hundred ninety-three million, six hundred fifty-three thousand, nine hundred thirteen".