43664639 has 2 divisors, whose sum is σ = 43664640. Its totient is φ = 43664638.

The previous prime is 43664629. The next prime is 43664659. The reversal of 43664639 is 93646634.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43664639 - 2¹² = 43660543 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 43664596 and 43664605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43664609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21832319 + 21832320.

It is an arithmetic number, because the mean of its divisors is an integer number (21832320).

Almost surely, 2^43664639 is an apocalyptic number.

43664639 is a deficient number, since it is larger than the sum of its proper divisors (1).

43664639 is an equidigital number, since it uses as much as digits as its factorization.

43664639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 41.

The square root of 43664639 is about 6607.9224420388. The cubic root of 43664639 is about 352.1356199819.

The spelling of 43664639 in words is "forty-three million, six hundred sixty-four thousand, six hundred thirty-nine".