21774512369 has 2 divisors, whose sum is σ = 21774512370. Its totient is φ = 21774512368.

The previous prime is 21774512327. The next prime is 21774512401. The reversal of 21774512369 is 96321547712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13183632400 + 8590879969 = 114820^2 + 92687^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21774512369 is a prime.

It is a super-2 number, since 2×21774512369² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21774512869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887256184 + 10887256185.

It is an arithmetic number, because the mean of its divisors is an integer number (10887256185).

Almost surely, 2^21774512369 is an apocalyptic number.

It is an amenable number.

21774512369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21774512369 is an equidigital number, since it uses as much as digits as its factorization.

21774512369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 47.

The spelling of 21774512369 in words is "twenty-one billion, seven hundred seventy-four million, five hundred twelve thousand, three hundred sixty-nine".