820603956517 has 2 divisors, whose sum is σ = 820603956518. Its totient is φ = 820603956516.

The previous prime is 820603956479. The next prime is 820603956521. The reversal of 820603956517 is 715659306028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 502920670561 + 317683285956 = 709169^2 + 563634^2 .

It is a cyclic number.

It is not a de Polignac number, because 820603956517 - 2¹⁵ = 820603923749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820603956547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410301978258 + 410301978259.

It is an arithmetic number, because the mean of its divisors is an integer number (410301978259).

Almost surely, 2^820603956517 is an apocalyptic number.

It is an amenable number.

820603956517 is a deficient number, since it is larger than the sum of its proper divisors (1).

820603956517 is an equidigital number, since it uses as much as digits as its factorization.

820603956517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2721600, while the sum is 52.

The spelling of 820603956517 in words is "eight hundred twenty billion, six hundred three million, nine hundred fifty-six thousand, five hundred seventeen".