997720 has 16 divisors (see below), whose sum is σ = 2244960. Its totient is φ = 399072.

The previous prime is 997699. The next prime is 997727. The reversal of 997720 is 27799.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12432 + ... + 12511.

It is an arithmetic number, because the mean of its divisors is an integer number (140310).

2⁹⁹⁷⁷²⁰ is an apocalyptic number.

It is an amenable number.

997720 is an abundant number, since it is smaller than the sum of its proper divisors (1247240).

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

997720 is a wasteful number, since it uses less digits than its factorization.

997720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24954 (or 24950 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 34.

The square root of 997720 is about 998.8593494582. The cubic root of 997720 is about 99.9239421667.

The spelling of 997720 in words is "nine hundred ninety-seven thousand, seven hundred twenty".