243705989 has 4 divisors (see below), whose sum is σ = 256532640. Its totient is φ = 230879340.

The previous prime is 243705977. The next prime is 243706019. The reversal of 243705989 is 989507342.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243705989 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 (243705949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6413297 + ... + 6413334.

It is an arithmetic number, because the mean of its divisors is an integer number (64133160).

Almost surely, 2^243705989 is an apocalyptic number.

It is an amenable number.

243705989 is a deficient number, since it is larger than the sum of its proper divisors (12826651).

243705989 is a wasteful number, since it uses less digits than its factorization.

243705989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12826650.

The product of its (nonzero) digits is 544320, while the sum is 47.

The square root of 243705989 is about 15611.0854523316. The cubic root of 243705989 is about 624.6288903011.

The spelling of 243705989 in words is "two hundred forty-three million, seven hundred five thousand, nine hundred eighty-nine".