243400421 has 16 divisors (see below), whose sum is σ = 278328960. Its totient is φ = 210693120.

The previous prime is 243400403. The next prime is 243400427. The reversal of 243400421 is 124004342.

It is not a de Polignac number, because 243400421 - 2¹⁸ = 243138277 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 243400393 and 243400402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243400427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56885 + ... + 61013.

It is an arithmetic number, because the mean of its divisors is an integer number (17395560).

Almost surely, 2^243400421 is an apocalyptic number.

It is an amenable number.

243400421 is a deficient number, since it is larger than the sum of its proper divisors (34928539).

243400421 is a wasteful number, since it uses less digits than its factorization.

243400421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4396.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 243400421 is about 15601.2954910802. The cubic root of 243400421 is about 624.3677198239.

Adding to 243400421 its reverse (124004342), we get a palindrome (367404763).

The spelling of 243400421 in words is "two hundred forty-three million, four hundred thousand, four hundred twenty-one".