243566421 has 16 divisors (see below), whose sum is σ = 371660928. Its totient is φ = 138988800.

The previous prime is 243566417. The next prime is 243566443. The reversal of 243566421 is 124665342.

It is not a de Polignac number, because 243566421 - 2² = 243566417 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243566221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8361 + ... + 23601.

It is an arithmetic number, because the mean of its divisors is an integer number (23228808).

Almost surely, 2^243566421 is an apocalyptic number.

243566421 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

243566421 is a deficient number, since it is larger than the sum of its proper divisors (128094507).

243566421 is a wasteful number, since it uses less digits than its factorization.

243566421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16012.

The product of its digits is 34560, while the sum is 33.

The square root of 243566421 is about 15606.6146553312. The cubic root of 243566421 is about 624.5096279437.

The spelling of 243566421 in words is "two hundred forty-three million, five hundred sixty-six thousand, four hundred twenty-one".