243240551 has 4 divisors (see below), whose sum is σ = 248897352. Its totient is φ = 237583752.

The previous prime is 243240509. The next prime is 243240559. The reversal of 243240551 is 155042342.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 243240551 - 2²⁶ = 176131687 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 243240551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243240559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2828336 + ... + 2828421.

It is an arithmetic number, because the mean of its divisors is an integer number (62224338).

Almost surely, 2^243240551 is an apocalyptic number.

243240551 is a deficient number, since it is larger than the sum of its proper divisors (5656801).

243240551 is an equidigital number, since it uses as much as digits as its factorization.

243240551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5656800.

The product of its (nonzero) digits is 4800, while the sum is 26.

The square root of 243240551 is about 15596.1710365076. The cubic root of 243240551 is about 624.2309910418.

Adding to 243240551 its reverse (155042342), we get a palindrome (398282893).

The spelling of 243240551 in words is "two hundred forty-three million, two hundred forty thousand, five hundred fifty-one".