997890 has 64 divisors (see below), whose sum is σ = 2626560. Its totient is φ = 241920.

The previous prime is 997889. The next prime is 997891. The reversal of 997890 is 98799.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (997889) and next prime (997891).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (997891) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26952 + ... + 26988.

It is an arithmetic number, because the mean of its divisors is an integer number (41040).

2⁹⁹⁷⁸⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1313280).

997890 is an abundant number, since it is smaller than the sum of its proper divisors (1628670).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

997890 is a wasteful number, since it uses less digits than its factorization.

997890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107.

The product of its (nonzero) digits is 40824, while the sum is 42.

The square root of 997890 is about 998.9444428996. The cubic root of 997890 is about 99.9296171408.

The spelling of 997890 in words is "nine hundred ninety-seven thousand, eight hundred ninety".