42042109 has 2 divisors, whose sum is σ = 42042110. Its totient is φ = 42042108.

The previous prime is 42042103. The next prime is 42042151. The reversal of 42042109 is 90124024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38812900 + 3229209 = 6230^2 + 1797^2 .

It is a cyclic number.

It is not a de Polignac number, because 42042109 - 2⁷ = 42041981 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42042109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42042103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21021054 + 21021055.

It is an arithmetic number, because the mean of its divisors is an integer number (21021055).

Almost surely, 2^42042109 is an apocalyptic number.

It is an amenable number.

42042109 is a deficient number, since it is larger than the sum of its proper divisors (1).

42042109 is an equidigital number, since it uses as much as digits as its factorization.

42042109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 42042109 is about 6483.9886643948. The cubic root of 42042109 is about 347.7187939457.

The spelling of 42042109 in words is "forty-two million, forty-two thousand, one hundred nine".