243391921 has 8 divisors (see below), whose sum is σ = 246141504. Its totient is φ = 240649200.

The previous prime is 243391909. The next prime is 243391927. The reversal of 243391921 is 129193342.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 243391921 - 2⁷ = 243391793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243391927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106230 + ... + 108496.

It is an arithmetic number, because the mean of its divisors is an integer number (30767688).

Almost surely, 2^243391921 is an apocalyptic number.

It is an amenable number.

243391921 is a deficient number, since it is larger than the sum of its proper divisors (2749583).

243391921 is a wasteful number, since it uses less digits than its factorization.

243391921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3431.

The product of its digits is 11664, while the sum is 34.

The square root of 243391921 is about 15601.0230754268. The cubic root of 243391921 is about 624.3604517080.

The spelling of 243391921 in words is "two hundred forty-three million, three hundred ninety-one thousand, nine hundred twenty-one".