243043551 has 16 divisors (see below), whose sum is σ = 361509120. Its totient is φ = 161379000.

The previous prime is 243043547. The next prime is 243043589. The reversal of 243043551 is 155340342.

243043551 is a `hidden beast` number, since 2 + 4 + 304 + 355 + 1 = 666.

It is not a de Polignac number, because 243043551 - 2² = 243043547 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243043511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11155 + ... + 24708.

It is an arithmetic number, because the mean of its divisors is an integer number (22594320).

Almost surely, 2^243043551 is an apocalyptic number.

243043551 is a deficient number, since it is larger than the sum of its proper divisors (118465569).

243043551 is a wasteful number, since it uses less digits than its factorization.

243043551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36123 (or 36117 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

The square root of 243043551 is about 15589.8541045130. The cubic root of 243043551 is about 624.0624244132.

Adding to 243043551 its reverse (155340342), we get a palindrome (398383893).

The spelling of 243043551 in words is "two hundred forty-three million, forty-three thousand, five hundred fifty-one".