42781009 has 4 divisors (see below), whose sum is σ = 43159716. Its totient is φ = 42402304.

The previous prime is 42781007. The next prime is 42781019. The reversal of 42781009 is 90018724.

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 595984 + 42185025 = 772^2 + 6495^2 .

It is a cyclic number.

It is not a de Polignac number, because 42781009 - 2¹ = 42781007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42781007) 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, 189184 + ... + 189409.

It is an arithmetic number, because the mean of its divisors is an integer number (10789929).

Almost surely, 2^42781009 is an apocalyptic number.

It is an amenable number.

42781009 is a deficient number, since it is larger than the sum of its proper divisors (378707).

42781009 is a wasteful number, since it uses less digits than its factorization.

42781009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378706.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 42781009 is about 6540.7193029513. The cubic root of 42781009 is about 349.7440550573.

The spelling of 42781009 in words is "forty-two million, seven hundred eighty-one thousand, nine".