42139109 has 2 divisors, whose sum is σ = 42139110. Its totient is φ = 42139108.

The previous prime is 42139087. The next prime is 42139121. The reversal of 42139109 is 90193124.

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., 36602500 + 5536609 = 6050^2 + 2353^2 .

It is a cyclic number.

It is not a de Polignac number, because 42139109 - 2¹² = 42135013 is a prime.

It is a Sophie Germain 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 (42139309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21069554 + 21069555.

It is an arithmetic number, because the mean of its divisors is an integer number (21069555).

Almost surely, 2^42139109 is an apocalyptic number.

It is an amenable number.

42139109 is a deficient number, since it is larger than the sum of its proper divisors (1).

42139109 is an equidigital number, since it uses as much as digits as its factorization.

42139109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 42139109 is about 6491.4643186264. The cubic root of 42139109 is about 347.9860087078.

The spelling of 42139109 in words is "forty-two million, one hundred thirty-nine thousand, one hundred nine".