42780905 has 4 divisors (see below), whose sum is σ = 51337092. Its totient is φ = 34224720.

The previous prime is 42780869. The next prime is 42780919. The reversal of 42780905 is 50908724.

It is a happy number.

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 26491609 + 16289296 = 5147^2 + 4036^2 .

It is not a de Polignac number, because 42780905 - 2⁸ = 42780649 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4278086 + ... + 4278095.

It is an arithmetic number, because the mean of its divisors is an integer number (12834273).

Almost surely, 2^42780905 is an apocalyptic number.

It is an amenable number.

42780905 is a deficient number, since it is larger than the sum of its proper divisors (8556187).

42780905 is an equidigital number, since it uses as much as digits as its factorization.

42780905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8556186.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 42780905 is about 6540.7113527506. The cubic root of 42780905 is about 349.7437716495.

The spelling of 42780905 in words is "forty-two million, seven hundred eighty thousand, nine hundred five".