240638309 has 2 divisors, whose sum is σ = 240638310. Its totient is φ = 240638308.

The previous prime is 240638273. The next prime is 240638311. The reversal of 240638309 is 903836042.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208715809 + 31922500 = 14447^2 + 5650^2 .

It is a cyclic number.

It is not a de Polignac number, because 240638309 - 2¹² = 240634213 is a prime.

It is a Sophie Germain prime.

Together with 240638311, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (240638369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 120319154 + 120319155.

It is an arithmetic number, because the mean of its divisors is an integer number (120319155).

Almost surely, 2^240638309 is an apocalyptic number.

It is an amenable number.

240638309 is a deficient number, since it is larger than the sum of its proper divisors (1).

240638309 is an equidigital number, since it uses as much as digits as its factorization.

240638309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 240638309 is about 15512.5210394700. The cubic root of 240638309 is about 621.9969508368.

The spelling of 240638309 in words is "two hundred forty million, six hundred thirty-eight thousand, three hundred nine".