243649 has 4 divisors (see below), whose sum is σ = 278464. Its totient is φ = 208836.

The previous prime is 243647. The next prime is 243671. The reversal of 243649 is 946342.

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.

It is a cyclic number.

It is not a de Polignac number, because 243649 - 2¹ = 243647 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17397 + ... + 17410.

It is an arithmetic number, because the mean of its divisors is an integer number (69616).

2²⁴³⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

243649 is a deficient number, since it is larger than the sum of its proper divisors (34815).

243649 is an equidigital number, since it uses as much as digits as its factorization.

243649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34814.

The product of its digits is 5184, while the sum is 28.

The square root of 243649 is about 493.6081441792. The cubic root of 243649 is about 62.4580198089.

It can be divided in two parts, 2436 and 49, that added together give a triangular number (2485 = T₇₀).

The spelling of 243649 in words is "two hundred forty-three thousand, six hundred forty-nine".