243421551 has 32 divisors (see below), whose sum is σ = 375782400. Its totient is φ = 155597760.

The previous prime is 243421543. The next prime is 243421609. The reversal of 243421551 is 155124342.

243421551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 243421551 - 2³ = 243421543 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 (243421511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 63450 + ... + 67176.

It is an arithmetic number, because the mean of its divisors is an integer number (11743200).

Almost surely, 2^243421551 is an apocalyptic number.

243421551 is a deficient number, since it is larger than the sum of its proper divisors (132360849).

243421551 is a wasteful number, since it uses less digits than its factorization.

243421551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3836 (or 3830 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 243421551 is about 15601.9726637371. The cubic root of 243421551 is about 624.3857867718.

Adding to 243421551 its reverse (155124342), we get a palindrome (398545893).

The spelling of 243421551 in words is "two hundred forty-three million, four hundred twenty-one thousand, five hundred fifty-one".