21376683575521 has 2 divisors, whose sum is σ = 21376683575522. Its totient is φ = 21376683575520.

The previous prime is 21376683575479. The next prime is 21376683575567. The reversal of 21376683575521 is 12557538667312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20898283103296 + 478400472225 = 4571464^2 + 691665^2 .

It is a cyclic number.

It is not a de Polignac number, because 21376683575521 - 2¹⁹ = 21376683051233 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21376683575521.

It is not a weakly prime, because it can be changed into another prime (21376683570521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10688341787760 + 10688341787761.

It is an arithmetic number, because the mean of its divisors is an integer number (10688341787761).

Almost surely, 2^{21376683575521} is an apocalyptic number.

It is an amenable number.

21376683575521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21376683575521 is an equidigital number, since it uses as much as digits as its factorization.

21376683575521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504000, while the sum is 61.

The spelling of 21376683575521 in words is "twenty-one trillion, three hundred seventy-six billion, six hundred eighty-three million, five hundred seventy-five thousand, five hundred twenty-one".