43640243 has 2 divisors, whose sum is σ = 43640244. Its totient is φ = 43640242.

The previous prime is 43640239. The next prime is 43640251. The reversal of 43640243 is 34204634.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43640243 - 2² = 43640239 is a prime.

It is equal to p_2640950 and since 43640243 and 2640950 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (43640843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21820121 + 21820122.

It is an arithmetic number, because the mean of its divisors is an integer number (21820122).

Almost surely, 2^43640243 is an apocalyptic number.

43640243 is a deficient number, since it is larger than the sum of its proper divisors (1).

43640243 is an equidigital number, since it uses as much as digits as its factorization.

43640243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 43640243 is about 6606.0762181495. The cubic root of 43640243 is about 352.0700268522.

Adding to 43640243 its reverse (34204634), we get a palindrome (77844877).

The spelling of 43640243 in words is "forty-three million, six hundred forty thousand, two hundred forty-three".