997740 has 72 divisors (see below), whose sum is σ = 3171168. Its totient is φ = 253440.

The previous prime is 997739. The next prime is 997741. The reversal of 997740 is 47799.

It is an interprime number because it is at equal distance from previous prime (997739) and next prime (997741).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 997695 and 997704.

It is not an unprimeable number, because it can be changed into a prime (997741) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4020 + ... + 4260.

It is an arithmetic number, because the mean of its divisors is an integer number (44044).

2⁹⁹⁷⁷⁴⁰ is an apocalyptic number.

997740 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1585584).

997740 is an abundant number, since it is smaller than the sum of its proper divisors (2173428).

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

997740 is a wasteful number, since it uses less digits than its factorization.

997740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 997740 is about 998.8693608275. The cubic root of 997740 is about 99.9246098442.

The spelling of 997740 in words is "nine hundred ninety-seven thousand, seven hundred forty".