42640309 has 2 divisors, whose sum is σ = 42640310. Its totient is φ = 42640308.

The previous prime is 42640289. The next prime is 42640331. The reversal of 42640309 is 90304624.

42640309 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32239684 + 10400625 = 5678^2 + 3225^2 .

It is a cyclic number.

It is not a de Polignac number, because 42640309 - 2⁷ = 42640181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42440309) 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 as a sum of consecutive naturals, namely, 21320154 + 21320155.

It is an arithmetic number, because the mean of its divisors is an integer number (21320155).

Almost surely, 2^42640309 is an apocalyptic number.

It is an amenable number.

42640309 is a deficient number, since it is larger than the sum of its proper divisors (1).

42640309 is an equidigital number, since it uses as much as digits as its factorization.

42640309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 42640309 is about 6529.9547471633. The cubic root of 42640309 is about 349.3602162516.

The spelling of 42640309 in words is "forty-two million, six hundred forty thousand, three hundred nine".