243999973 has 4 divisors (see below), whose sum is σ = 278857120. Its totient is φ = 209142828.

The previous prime is 243999971. The next prime is 243999991. The reversal of 243999973 is 379999342.

243999973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 243999973 - 2¹ = 243999971 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 (243999971) 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, 17428563 + ... + 17428576.

It is an arithmetic number, because the mean of its divisors is an integer number (69714280).

Almost surely, 2^243999973 is an apocalyptic number.

It is an amenable number.

243999973 is a deficient number, since it is larger than the sum of its proper divisors (34857147).

243999973 is an equidigital number, since it uses as much as digits as its factorization.

243999973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34857146.

The product of its digits is 3306744, while the sum is 55.

The square root of 243999973 is about 15620.4984875643. The cubic root of 243999973 is about 624.8799539038.

The spelling of 243999973 in words is "two hundred forty-three million, nine hundred ninety-nine thousand, nine hundred seventy-three".