42939509 has 2 divisors, whose sum is σ = 42939510. Its totient is φ = 42939508.

The previous prime is 42939503. The next prime is 42939511. The reversal of 42939509 is 90593924.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31696900 + 11242609 = 5630^2 + 3353^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42939509 is a prime.

It is a super-2 number, since 2×42939509² = 3687602866322162, which contains 22 as substring.

Together with 42939511, 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 (42939503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21469754 + 21469755.

It is an arithmetic number, because the mean of its divisors is an integer number (21469755).

Almost surely, 2^42939509 is an apocalyptic number.

It is an amenable number.

42939509 is a deficient number, since it is larger than the sum of its proper divisors (1).

42939509 is an equidigital number, since it uses as much as digits as its factorization.

42939509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 87480, while the sum is 41.

The square root of 42939509 is about 6552.8245055091. The cubic root of 42939509 is about 350.1754467319.

The spelling of 42939509 in words is "forty-two million, nine hundred thirty-nine thousand, five hundred nine".