521971232309 has 2 divisors, whose sum is σ = 521971232310. Its totient is φ = 521971232308.

The previous prime is 521971232249. The next prime is 521971232339. The reversal of 521971232309 is 903232179125.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 518656351684 + 3314880625 = 720178^2 + 57575^2 .

It is a cyclic number.

It is not a de Polignac number, because 521971232309 - 2³⁶ = 453251755573 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 521971232309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521971232339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260985616154 + 260985616155.

It is an arithmetic number, because the mean of its divisors is an integer number (260985616155).

Almost surely, 2^521971232309 is an apocalyptic number.

It is an amenable number.

521971232309 is a deficient number, since it is larger than the sum of its proper divisors (1).

521971232309 is an equidigital number, since it uses as much as digits as its factorization.

521971232309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 204120, while the sum is 44.

The spelling of 521971232309 in words is "five hundred twenty-one billion, nine hundred seventy-one million, two hundred thirty-two thousand, three hundred nine".