42508309 has 2 divisors, whose sum is σ = 42508310. Its totient is φ = 42508308.

The previous prime is 42508243. The next prime is 42508327. The reversal of 42508309 is 90380524.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39652209 + 2856100 = 6297^2 + 1690^2 .

It is a cyclic number.

It is not a de Polignac number, because 42508309 - 2⁷ = 42508181 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 (42502309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21254154 + 21254155.

It is an arithmetic number, because the mean of its divisors is an integer number (21254155).

Almost surely, 2^42508309 is an apocalyptic number.

It is an amenable number.

42508309 is a deficient number, since it is larger than the sum of its proper divisors (1).

42508309 is an equidigital number, since it uses as much as digits as its factorization.

42508309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 42508309 is about 6519.8396452674. The cubic root of 42508309 is about 348.9993431897. Note that the first 3 decimals are identical.

The spelling of 42508309 in words is "forty-two million, five hundred eight thousand, three hundred nine".