42045209 has 4 divisors (see below), whose sum is σ = 43181604. Its totient is φ = 40908816.

The previous prime is 42045203. The next prime is 42045217. The reversal of 42045209 is 90254024.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40896025 + 1149184 = 6395^2 + 1072^2 .

It is a cyclic number.

It is not a de Polignac number, because 42045209 - 2²⁴ = 25267993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42045203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 568142 + ... + 568215.

It is an arithmetic number, because the mean of its divisors is an integer number (10795401).

Almost surely, 2^42045209 is an apocalyptic number.

It is an amenable number.

42045209 is a deficient number, since it is larger than the sum of its proper divisors (1136395).

42045209 is a wasteful number, since it uses less digits than its factorization.

42045209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1136394.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 42045209 is about 6484.2277103754. The cubic root of 42045209 is about 347.7273401533.

The spelling of 42045209 in words is "forty-two million, forty-five thousand, two hundred nine".