521509997 has 2 divisors, whose sum is σ = 521509998. Its totient is φ = 521509996.

The previous prime is 521509951. The next prime is 521510009. The reversal of 521509997 is 799905125.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 424112836 + 97397161 = 20594^2 + 9869^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521509997 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521509907) 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, 260754998 + 260754999.

It is an arithmetic number, because the mean of its divisors is an integer number (260754999).

Almost surely, 2^521509997 is an apocalyptic number.

It is an amenable number.

521509997 is a deficient number, since it is larger than the sum of its proper divisors (1).

521509997 is an equidigital number, since it uses as much as digits as its factorization.

521509997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 255150, while the sum is 47.

The square root of 521509997 is about 22836.5933755453. The cubic root of 521509997 is about 804.9227692327.

The spelling of 521509997 in words is "five hundred twenty-one million, five hundred nine thousand, nine hundred ninety-seven".