243421605 has 48 divisors (see below), whose sum is σ = 500083584. Its totient is φ = 111274560.

The previous prime is 243421543. The next prime is 243421609. The reversal of 243421605 is 506124342.

243421605 is a `hidden beast` number, since 2 + 4 + 34 + 21 + 605 = 666.

It is not a de Polignac number, because 243421605 - 2⁸ = 243421349 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 (243421609) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5806 + ... + 22815.

It is an arithmetic number, because the mean of its divisors is an integer number (10418408).

Almost surely, 2^243421605 is an apocalyptic number.

It is an amenable number.

243421605 is an abundant number, since it is smaller than the sum of its proper divisors (256661979).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

243421605 is an equidigital number, since it uses as much as digits as its factorization.

243421605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28648 (or 28636 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 243421605 is about 15601.9743942874. The cubic root of 243421605 is about 624.3858329425.

Adding to 243421605 its reverse (506124342), we get a palindrome (749545947).

It can be divided in two parts, 24 and 3421605, that multiplied together give a triangular number (82118520 = T₁₂₈₁₅).

The spelling of 243421605 in words is "two hundred forty-three million, four hundred twenty-one thousand, six hundred five".