997859 has 4 divisors (see below), whose sum is σ = 1030080. Its totient is φ = 965640.

The previous prime is 997813. The next prime is 997877. The reversal of 997859 is 958799.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 997859 - 2¹² = 993763 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (997879) 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, 16064 + ... + 16125.

It is an arithmetic number, because the mean of its divisors is an integer number (257520).

2⁹⁹⁷⁸⁵⁹ is an apocalyptic number.

997859 is a deficient number, since it is larger than the sum of its proper divisors (32221).

997859 is a wasteful number, since it uses less digits than its factorization.

997859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32220.

The product of its digits is 204120, while the sum is 47.

The square root of 997859 is about 998.9289264007. The cubic root of 997859 is about 99.9285823407.

Subtracting from 997859 its reverse (958799), we obtain a triangular number (39060 = T₂₇₉).

The spelling of 997859 in words is "nine hundred ninety-seven thousand, eight hundred fifty-nine".