243409999 has 12 divisors (see below), whose sum is σ = 283428624. Its totient is φ = 208432224.

The previous prime is 243409979. The next prime is 243410003. The reversal of 243409999 is 999904342.

It is not a de Polignac number, because 243409999 - 2⁷ = 243409871 is a prime.

It is a super-2 number, since 2×243409999² = 118496855226360002, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243409979) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69187 + ... + 72619.

It is an arithmetic number, because the mean of its divisors is an integer number (23619052).

Almost surely, 2^243409999 is an apocalyptic number.

243409999 is a deficient number, since it is larger than the sum of its proper divisors (40018625).

243409999 is a wasteful number, since it uses less digits than its factorization.

243409999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4894 (or 4887 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 49.

The square root of 243409999 is about 15601.6024497486. The cubic root of 243409999 is about 624.3759095051.

The spelling of 243409999 in words is "two hundred forty-three million, four hundred nine thousand, nine hundred ninety-nine".