997591 has 6 divisors (see below), whose sum is σ = 1160520. Its totient is φ = 855036.

The previous prime is 997589. The next prime is 997597. The reversal of 997591 is 195799.

997591 = T₃₅ + T₃₆ + ... + T₁₈₁.

It is not a de Polignac number, because 997591 - 2¹ = 997589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997597) 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 5 ways as a sum of consecutive naturals, for example, 10131 + ... + 10228.

It is an arithmetic number, because the mean of its divisors is an integer number (193420).

2⁹⁹⁷⁵⁹¹ is an apocalyptic number.

997591 is a deficient number, since it is larger than the sum of its proper divisors (162929).

997591 is a wasteful number, since it uses less digits than its factorization.

997591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20373 (or 20366 counting only the distinct ones).

The product of its digits is 25515, while the sum is 40.

The square root of 997591 is about 998.7947737148. The cubic root of 997591 is about 99.9196354327.

The spelling of 997591 in words is "nine hundred ninety-seven thousand, five hundred ninety-one".