997819 has 4 divisors (see below), whose sum is σ = 1002760. Its totient is φ = 992880.

The previous prime is 997813. The next prime is 997877. The reversal of 997819 is 918799.

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 997819 - 2³ = 997811 is a prime.

It is a super-2 number, since 2×997819² = 1991285513522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2154 + ... + 2575.

It is an arithmetic number, because the mean of its divisors is an integer number (250690).

2⁹⁹⁷⁸¹⁹ is an apocalyptic number.

997819 is a deficient number, since it is larger than the sum of its proper divisors (4941).

997819 is a wasteful number, since it uses less digits than its factorization.

997819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4940.

The product of its digits is 40824, while the sum is 43.

The square root of 997819 is about 998.9089047556. The cubic root of 997819 is about 99.9272470830.

The spelling of 997819 in words is "nine hundred ninety-seven thousand, eight hundred nineteen".