817768993 has 4 divisors (see below), whose sum is σ = 817940160. Its totient is φ = 817597828.

The previous prime is 817768981. The next prime is 817768997. The reversal of 817768993 is 399867718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 817768993 - 2¹⁷ = 817637921 is a prime.

It is a super-2 number, since 2×817768993² = 1337492251824468098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (817768997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78205 + ... + 88042.

It is an arithmetic number, because the mean of its divisors is an integer number (204485040).

Almost surely, 2^817768993 is an apocalyptic number.

It is an amenable number.

817768993 is a deficient number, since it is larger than the sum of its proper divisors (171167).

817768993 is a wasteful number, since it uses less digits than its factorization.

817768993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171166.

The product of its digits is 4572288, while the sum is 58.

The square root of 817768993 is about 28596.6605218162. The cubic root of 817768993 is about 935.1405292698.

The spelling of 817768993 in words is "eight hundred seventeen million, seven hundred sixty-eight thousand, nine hundred ninety-three".