997691 has 8 divisors (see below), whose sum is σ = 1030080. Its totient is φ = 965952.

The previous prime is 997681. The next prime is 997693. The reversal of 997691 is 196799.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 997691 - 2⁶ = 997627 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997693) 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 7 ways as a sum of consecutive naturals, for example, 5681 + ... + 5853.

It is an arithmetic number, because the mean of its divisors is an integer number (128760).

2⁹⁹⁷⁶⁹¹ is an apocalyptic number.

997691 is a deficient number, since it is larger than the sum of its proper divisors (32389).

997691 is a wasteful number, since it uses less digits than its factorization.

997691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325.

The product of its digits is 30618, while the sum is 41.

The square root of 997691 is about 998.8448327944. The cubic root of 997691 is about 99.9229740185.

The spelling of 997691 in words is "nine hundred ninety-seven thousand, six hundred ninety-one".