42503309 has 2 divisors, whose sum is σ = 42503310. Its totient is φ = 42503308.

The previous prime is 42503273. The next prime is 42503311. The reversal of 42503309 is 90330524.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28590409 + 13912900 = 5347^2 + 3730^2 .

It is a cyclic number.

It is not a de Polignac number, because 42503309 - 2²⁰ = 41454733 is a prime.

Together with 42503311, 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 (42503339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21251654 + 21251655.

It is an arithmetic number, because the mean of its divisors is an integer number (21251655).

Almost surely, 2^42503309 is an apocalyptic number.

It is an amenable number.

42503309 is a deficient number, since it is larger than the sum of its proper divisors (1).

42503309 is an equidigital number, since it uses as much as digits as its factorization.

42503309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 26.

The square root of 42503309 is about 6519.4561889777. The cubic root of 42503309 is about 348.9856590796.

The spelling of 42503309 in words is "forty-two million, five hundred three thousand, three hundred nine".