243997 has 6 divisors (see below), whose sum is σ = 264698. Its totient is φ = 223584.

The previous prime is 243989. The next prime is 244003. The reversal of 243997 is 799342.

It can be written as a sum of positive squares in 3 ways, for example, as 19321 + 224676 = 139^2 + 474^2 .

It is not a de Polignac number, because 243997 - 2³ = 243989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243917) 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 5 ways as a sum of consecutive naturals, for example, 1713 + ... + 1849.

2²⁴³⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

243997 is a deficient number, since it is larger than the sum of its proper divisors (20701).

243997 is an equidigital number, since it uses as much as digits as its factorization.

243997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287 (or 150 counting only the distinct ones).

The product of its digits is 13608, while the sum is 34.

The square root of 243997 is about 493.9605247386. The cubic root of 243997 is about 62.4877415959.

The spelling of 243997 in words is "two hundred forty-three thousand, nine hundred ninety-seven".