21231635775769 has 2 divisors, whose sum is σ = 21231635775770. Its totient is φ = 21231635775768.

The previous prime is 21231635775683. The next prime is 21231635775841. The reversal of 21231635775769 is 96757753613212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16956169777369 + 4275465998400 = 4117787^2 + 2067720^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231635775769 - 2¹¹ = 21231635773721 is a prime.

It is a super-2 number, since 2×21231635775769² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21231635775769.

It is not a weakly prime, because it can be changed into another prime (21231635775569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615817887884 + 10615817887885.

It is an arithmetic number, because the mean of its divisors is an integer number (10615817887885).

Almost surely, 2^{21231635775769} is an apocalyptic number.

It is an amenable number.

21231635775769 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231635775769 is an equidigital number, since it uses as much as digits as its factorization.

21231635775769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100018800, while the sum is 64.

The spelling of 21231635775769 in words is "twenty-one trillion, two hundred thirty-one billion, six hundred thirty-five million, seven hundred seventy-five thousand, seven hundred sixty-nine".