243990 has 24 divisors (see below), whose sum is σ = 634608. Its totient is φ = 65040.

The previous prime is 243989. The next prime is 244003. The reversal of 243990 is 99342.

It is a super-2 number, since 2×243990² = 119062240200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1266 + ... + 1445.

It is an arithmetic number, because the mean of its divisors is an integer number (26442).

2²⁴³⁹⁹⁰ is an apocalyptic number.

243990 is an abundant number, since it is smaller than the sum of its proper divisors (390618).

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

243990 is a wasteful number, since it uses less digits than its factorization.

243990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2724 (or 2721 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 243990 is about 493.9534391013. The cubic root of 243990 is about 62.4871440224.

The spelling of 243990 in words is "two hundred forty-three thousand, nine hundred ninety".