42665581 has 4 divisors (see below), whose sum is σ = 48760672. Its totient is φ = 36570492.

The previous prime is 42665561. The next prime is 42665593. The reversal of 42665581 is 18556624.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 42665581 - 2⁵ = 42665549 is a prime.

It is a super-2 number, since 2×42665581² = 3640703604135122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42665581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42665561) 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, 3047535 + ... + 3047548.

It is an arithmetic number, because the mean of its divisors is an integer number (12190168).

Almost surely, 2^42665581 is an apocalyptic number.

It is an amenable number.

42665581 is a deficient number, since it is larger than the sum of its proper divisors (6095091).

42665581 is an equidigital number, since it uses as much as digits as its factorization.

42665581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6095090.

The product of its digits is 57600, while the sum is 37.

The square root of 42665581 is about 6531.8895428505. The cubic root of 42665581 is about 349.4292220657.

The spelling of 42665581 in words is "forty-two million, six hundred sixty-five thousand, five hundred eighty-one".