517219921 has 2 divisors, whose sum is σ = 517219922. Its totient is φ = 517219920.

The previous prime is 517219909. The next prime is 517219931. The reversal of 517219921 is 129912715.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 311699025 + 205520896 = 17655^2 + 14336^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-517219921 is a prime.

It is not a weakly prime, because it can be changed into another prime (517219931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258609960 + 258609961.

It is an arithmetic number, because the mean of its divisors is an integer number (258609961).

Almost surely, 2^517219921 is an apocalyptic number.

It is an amenable number.

517219921 is a deficient number, since it is larger than the sum of its proper divisors (1).

517219921 is an equidigital number, since it uses as much as digits as its factorization.

517219921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 37.

The square root of 517219921 is about 22742.4695448845. The cubic root of 517219921 is about 802.7095216096.

The spelling of 517219921 in words is "five hundred seventeen million, two hundred nineteen thousand, nine hundred twenty-one".