21100122156613 has 2 divisors, whose sum is σ = 21100122156614. Its totient is φ = 21100122156612.

The previous prime is 21100122156587. The next prime is 21100122156667. The reversal of 21100122156613 is 31665122100112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20671780704129 + 428341452484 = 4546623^2 + 654478^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21100122156613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100122196613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550061078306 + 10550061078307.

It is an arithmetic number, because the mean of its divisors is an integer number (10550061078307).

Almost surely, 2^{21100122156613} is an apocalyptic number.

It is an amenable number.

21100122156613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100122156613 is an equidigital number, since it uses as much as digits as its factorization.

21100122156613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

Adding to 21100122156613 its reverse (31665122100112), we get a palindrome (52765244256725).

The spelling of 21100122156613 in words is "twenty-one trillion, one hundred billion, one hundred twenty-two million, one hundred fifty-six thousand, six hundred thirteen".