42440081 has 4 divisors (see below), whose sum is σ = 42514212. Its totient is φ = 42365952.

The previous prime is 42440077. The next prime is 42440093. The reversal of 42440081 is 18004424.

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 33825856 + 8614225 = 5816^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 42440081 - 2² = 42440077 is a prime.

It is a super-2 number, since 2×42440081² = 3602320950573122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42440051) 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, 36200 + ... + 37353.

It is an arithmetic number, because the mean of its divisors is an integer number (10628553).

Almost surely, 2^42440081 is an apocalyptic number.

It is an amenable number.

42440081 is a deficient number, since it is larger than the sum of its proper divisors (74131).

42440081 is an equidigital number, since it uses as much as digits as its factorization.

42440081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74130.

The product of its (nonzero) digits is 1024, while the sum is 23.

The square root of 42440081 is about 6514.6052067643. The cubic root of 42440081 is about 348.8125226309.

The spelling of 42440081 in words is "forty-two million, four hundred forty thousand, eighty-one".