21318277281253 has 2 divisors, whose sum is σ = 21318277281254. Its totient is φ = 21318277281252.

The previous prime is 21318277281239. The next prime is 21318277281319. The reversal of 21318277281253 is 35218277281312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21308582318884 + 9694962369 = 4616122^2 + 98463^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21318277281253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21318277281253.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21318277281233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10659138640626 + 10659138640627.

It is an arithmetic number, because the mean of its divisors is an integer number (10659138640627).

Almost surely, 2^{21318277281253} is an apocalyptic number.

It is an amenable number.

21318277281253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21318277281253 is an equidigital number, since it uses as much as digits as its factorization.

21318277281253 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2257920, while the sum is 52.

The spelling of 21318277281253 in words is "twenty-one trillion, three hundred eighteen billion, two hundred seventy-seven million, two hundred eighty-one thousand, two hundred fifty-three".