42391309 has 2 divisors, whose sum is σ = 42391310. Its totient is φ = 42391308.

The previous prime is 42391303. The next prime is 42391339. The reversal of 42391309 is 90319324.

42391309 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., 40576900 + 1814409 = 6370^2 + 1347^2 .

It is a cyclic number.

It is not a de Polignac number, because 42391309 - 2⁹ = 42390797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42391303) 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, 21195654 + 21195655.

It is an arithmetic number, because the mean of its divisors is an integer number (21195655).

Almost surely, 2^42391309 is an apocalyptic number.

It is an amenable number.

42391309 is a deficient number, since it is larger than the sum of its proper divisors (1).

42391309 is an equidigital number, since it uses as much as digits as its factorization.

42391309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 42391309 is about 6510.8608493808. The cubic root of 42391309 is about 348.6788533499.

The spelling of 42391309 in words is "forty-two million, three hundred ninety-one thousand, three hundred nine".