42028181 has 4 divisors (see below), whose sum is σ = 45261132. Its totient is φ = 38795232.

The previous prime is 42028169. The next prime is 42028183. The reversal of 42028181 is 18182024.

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 8213956 + 33814225 = 2866^2 + 5815^2 .

It is a cyclic number.

It is not a de Polignac number, because 42028181 - 2⁶ = 42028117 is a prime.

It is a super-2 number, since 2×42028181² = 3532735996337522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 42028181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42028183) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1616456 + ... + 1616481.

It is an arithmetic number, because the mean of its divisors is an integer number (11315283).

Almost surely, 2^42028181 is an apocalyptic number.

It is an amenable number.

42028181 is a deficient number, since it is larger than the sum of its proper divisors (3232951).

42028181 is a wasteful number, since it uses less digits than its factorization.

42028181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3232950.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 42028181 is about 6482.9145451718. The cubic root of 42028181 is about 347.6803914775.

The spelling of 42028181 in words is "forty-two million, twenty-eight thousand, one hundred eighty-one".