43640239 has 2 divisors, whose sum is σ = 43640240. Its totient is φ = 43640238.

The previous prime is 43640189. The next prime is 43640243. The reversal of 43640239 is 93204634.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43640239 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 43640239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43640339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21820119 + 21820120.

It is an arithmetic number, because the mean of its divisors is an integer number (21820120).

Almost surely, 2^43640239 is an apocalyptic number.

43640239 is a deficient number, since it is larger than the sum of its proper divisors (1).

43640239 is an equidigital number, since it uses as much as digits as its factorization.

43640239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 43640239 is about 6606.0759153979. The cubic root of 43640239 is about 352.0700160955.

The spelling of 43640239 in words is "forty-three million, six hundred forty thousand, two hundred thirty-nine".