243856649 has 4 divisors (see below), whose sum is σ = 254459136. Its totient is φ = 233254164.

The previous prime is 243856609. The next prime is 243856651. The reversal of 243856649 is 946658342.

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 a de Polignac number, because none of the positive numbers 2^k-243856649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243856609) 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 3 ways as a sum of consecutive naturals, for example, 5301209 + ... + 5301254.

It is an arithmetic number, because the mean of its divisors is an integer number (63614784).

Almost surely, 2^243856649 is an apocalyptic number.

It is an amenable number.

243856649 is a deficient number, since it is larger than the sum of its proper divisors (10602487).

243856649 is a wasteful number, since it uses less digits than its factorization.

243856649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10602486.

The product of its digits is 1244160, while the sum is 47.

The square root of 243856649 is about 15615.9101239729. The cubic root of 243856649 is about 624.7575797974.

The spelling of 243856649 in words is "two hundred forty-three million, eight hundred fifty-six thousand, six hundred forty-nine".