243216731 has 4 divisors (see below), whose sum is σ = 251062464. Its totient is φ = 235371000.

The previous prime is 243216719. The next prime is 243216749. The reversal of 243216731 is 137612342.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243216731 is a prime.

It is a super-2 number, since 2×243216731² = 118308756476652722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 243216694 and 243216703.

It is not an unprimeable number, because it can be changed into a prime (243216761) 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, 3922820 + ... + 3922881.

It is an arithmetic number, because the mean of its divisors is an integer number (62765616).

Almost surely, 2^243216731 is an apocalyptic number.

243216731 is a deficient number, since it is larger than the sum of its proper divisors (7845733).

243216731 is an equidigital number, since it uses as much as digits as its factorization.

243216731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7845732.

The product of its digits is 6048, while the sum is 29.

The square root of 243216731 is about 15595.4073688378. The cubic root of 243216731 is about 624.2106138643.

The spelling of 243216731 in words is "two hundred forty-three million, two hundred sixteen thousand, seven hundred thirty-one".