243310721 has 4 divisors (see below), whose sum is σ = 253889472. Its totient is φ = 232731972.

The previous prime is 243310699. The next prime is 243310741. The reversal of 243310721 is 127013342.

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 not a de Polignac number, because 243310721 - 2²² = 239116417 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 10578727 = 243310721 / (2 + 4 + 3 + 3 + 1 + 0 + 7 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243310741) 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, 5289341 + ... + 5289386.

It is an arithmetic number, because the mean of its divisors is an integer number (63472368).

Almost surely, 2^243310721 is an apocalyptic number.

It is an amenable number.

243310721 is a deficient number, since it is larger than the sum of its proper divisors (10578751).

243310721 is a wasteful number, since it uses less digits than its factorization.

243310721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10578750.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 243310721 is about 15598.4204649061. The cubic root of 243310721 is about 624.2910112935.

The spelling of 243310721 in words is "two hundred forty-three million, three hundred ten thousand, seven hundred twenty-one".