1997720 has 16 divisors (see below), whose sum is σ = 4494960. Its totient is φ = 799072.

The previous prime is 1997719. The next prime is 1997731. The reversal of 1997720 is 277991.

It is a congruent number.

It is an unprimeable number.

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, 24932 + ... + 25011.

It is an arithmetic number, because the mean of its divisors is an integer number (280935).

2^1997720 is an apocalyptic number.

1997720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1997720 is an abundant number, since it is smaller than the sum of its proper divisors (2497240).

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

1997720 is a wasteful number, since it uses less digits than its factorization.

1997720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49954 (or 49950 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 35.

The square root of 1997720 is about 1413.4072307725. The cubic root of 1997720 is about 125.9442097848.

The spelling of 1997720 in words is "one million, nine hundred ninety-seven thousand, seven hundred twenty".