997817 has 4 divisors (see below), whose sum is σ = 1022196. Its totient is φ = 973440.

The previous prime is 997813. The next prime is 997877. The reversal of 997817 is 718799.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 718799 = 37 ⋅19427.

It can be written as a sum of positive squares in 2 ways, for example, as 602176 + 395641 = 776^2 + 629^2 .

It is a cyclic number.

It is not a de Polignac number, because 997817 - 2² = 997813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 24337 = 997817 / (9 + 9 + 7 + 8 + 1 + 7).

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 997817.

It is not an unprimeable number, because it can be changed into a prime (997811) 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, 12128 + ... + 12209.

It is an arithmetic number, because the mean of its divisors is an integer number (255549).

2⁹⁹⁷⁸¹⁷ is an apocalyptic number.

It is an amenable number.

997817 is a deficient number, since it is larger than the sum of its proper divisors (24379).

997817 is a wasteful number, since it uses less digits than its factorization.

997817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24378.

The product of its digits is 31752, while the sum is 41.

The square root of 997817 is about 998.9079036628. The cubic root of 997817 is about 99.9271803191.

The spelling of 997817 in words is "nine hundred ninety-seven thousand, eight hundred seventeen".