42216805 has 4 divisors (see below), whose sum is σ = 50660172. Its totient is φ = 33773440.

The previous prime is 42216791. The next prime is 42216809. The reversal of 42216805 is 50861224.

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 12383361 + 29833444 = 3519^2 + 5462^2 .

It is a de Polignac number, because none of the positive numbers 2^k-42216805 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42216809) 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, 4221676 + ... + 4221685.

It is an arithmetic number, because the mean of its divisors is an integer number (12665043).

Almost surely, 2^42216805 is an apocalyptic number.

It is an amenable number.

42216805 is a deficient number, since it is larger than the sum of its proper divisors (8443367).

42216805 is an equidigital number, since it uses as much as digits as its factorization.

42216805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8443366.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 42216805 is about 6497.4460367132. The cubic root of 42216805 is about 348.1997493522.

It can be divided in two parts, 4221 and 6805, that added together give a triangular number (11026 = T₁₄₈).

The spelling of 42216805 in words is "forty-two million, two hundred sixteen thousand, eight hundred five".