243215639 has 4 divisors (see below), whose sum is σ = 253790256. Its totient is φ = 232641024.

The previous prime is 243215629. The next prime is 243215653. The reversal of 243215639 is 936512342.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936512342 = 2 ⋅468256171.

It is a cyclic number.

It is not a de Polignac number, because 243215639 - 2⁸ = 243215383 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 243215599 and 243215608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243215629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5287274 + ... + 5287319.

It is an arithmetic number, because the mean of its divisors is an integer number (63447564).

Almost surely, 2^243215639 is an apocalyptic number.

243215639 is a deficient number, since it is larger than the sum of its proper divisors (10574617).

243215639 is a wasteful number, since it uses less digits than its factorization.

243215639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10574616.

The product of its digits is 38880, while the sum is 35.

The square root of 243215639 is about 15595.3723584915. The cubic root of 243215639 is about 624.2096796646.

The spelling of 243215639 in words is "two hundred forty-three million, two hundred fifteen thousand, six hundred thirty-nine".