42940309 has 2 divisors, whose sum is σ = 42940310. Its totient is φ = 42940308.

The previous prime is 42940307. The next prime is 42940343. The reversal of 42940309 is 90304924.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33466225 + 9474084 = 5785^2 + 3078^2 .

It is a cyclic number.

It is not a de Polignac number, because 42940309 - 2¹ = 42940307 is a prime.

Together with 42940307, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42940307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21470154 + 21470155.

It is an arithmetic number, because the mean of its divisors is an integer number (21470155).

Almost surely, 2^42940309 is an apocalyptic number.

It is an amenable number.

42940309 is a deficient number, since it is larger than the sum of its proper divisors (1).

42940309 is an equidigital number, since it uses as much as digits as its factorization.

42940309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 42940309 is about 6552.8855476042. The cubic root of 42940309 is about 350.1776214083.

The spelling of 42940309 in words is "forty-two million, nine hundred forty thousand, three hundred nine".