243877985 has 24 divisors (see below), whose sum is σ = 319172280. Its totient is φ = 178885824.

The previous prime is 243877981. The next prime is 243877999. The reversal of 243877985 is 589778342.

It can be written as a sum of positive squares in 12 ways, for example, as 221533456 + 22344529 = 14884^2 + 4727^2 .

It is not a de Polignac number, because 243877985 - 2² = 243877981 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243877981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1636691 + ... + 1636839.

It is an arithmetic number, because the mean of its divisors is an integer number (13298845).

Almost surely, 2^243877985 is an apocalyptic number.

It is an amenable number.

243877985 is a deficient number, since it is larger than the sum of its proper divisors (75294295).

243877985 is an frugal number, since it uses more digits than its factorization.

243877985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 167 counting only the distinct ones).

The product of its digits is 3386880, while the sum is 53.

The square root of 243877985 is about 15616.5932584543. The cubic root of 243877985 is about 624.7758001180.

The spelling of 243877985 in words is "two hundred forty-three million, eight hundred seventy-seven thousand, nine hundred eighty-five".