521540332393 has 2 divisors, whose sum is σ = 521540332394. Its totient is φ = 521540332392.

The previous prime is 521540332303. The next prime is 521540332403. The reversal of 521540332393 is 393233045125.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 285954354009 + 235585978384 = 534747^2 + 485372^2 .

It is a cyclic number.

It is not a de Polignac number, because 521540332393 - 2²⁹ = 521003461481 is a prime.

It is not a weakly prime, because it can be changed into another prime (521540332303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260770166196 + 260770166197.

It is an arithmetic number, because the mean of its divisors is an integer number (260770166197).

Almost surely, 2^521540332393 is an apocalyptic number.

It is an amenable number.

521540332393 is a deficient number, since it is larger than the sum of its proper divisors (1).

521540332393 is an equidigital number, since it uses as much as digits as its factorization.

521540332393 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 291600, while the sum is 40.

The spelling of 521540332393 in words is "five hundred twenty-one billion, five hundred forty million, three hundred thirty-two thousand, three hundred ninety-three".