521398667791 has 2 divisors, whose sum is σ = 521398667792. Its totient is φ = 521398667790.

The previous prime is 521398667761. The next prime is 521398667827. The reversal of 521398667791 is 197766893125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521398667791 - 2¹¹ = 521398665743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521398667761) 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, 260699333895 + 260699333896.

It is an arithmetic number, because the mean of its divisors is an integer number (260699333896).

Almost surely, 2^521398667791 is an apocalyptic number.

521398667791 is a deficient number, since it is larger than the sum of its proper divisors (1).

521398667791 is an equidigital number, since it uses as much as digits as its factorization.

521398667791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34292160, while the sum is 64.

The spelling of 521398667791 in words is "five hundred twenty-one billion, three hundred ninety-eight million, six hundred sixty-seven thousand, seven hundred ninety-one".