243210421 has 4 divisors (see below), whose sum is σ = 243327744. Its totient is φ = 243093100.

The previous prime is 243210419. The next prime is 243210433. The reversal of 243210421 is 124012342.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 124012342 = 2 ⋅62006171.

It is a cyclic number.

It is not a de Polignac number, because 243210421 - 2¹ = 243210419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243210521) 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 3 ways as a sum of consecutive naturals, for example, 55495 + ... + 59716.

It is an arithmetic number, because the mean of its divisors is an integer number (60831936).

Almost surely, 2^243210421 is an apocalyptic number.

It is an amenable number.

243210421 is a deficient number, since it is larger than the sum of its proper divisors (117323).

243210421 is a wasteful number, since it uses less digits than its factorization.

243210421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117322.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 243210421 is about 15595.2050643780. The cubic root of 243210421 is about 624.2052156570.

Adding to 243210421 its reverse (124012342), we get a palindrome (367222763).

The spelling of 243210421 in words is "two hundred forty-three million, two hundred ten thousand, four hundred twenty-one".