42543665 has 4 divisors (see below), whose sum is σ = 51052404. Its totient is φ = 34034928.

The previous prime is 42543653. The next prime is 42543671. The reversal of 42543665 is 56634524.

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 17783089 + 24760576 = 4217^2 + 4976^2 .

It is a cyclic number.

It is not a de Polignac number, because 42543665 - 2⁸ = 42543409 is a prime.

It is a Duffinian number.

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, 4254362 + ... + 4254371.

It is an arithmetic number, because the mean of its divisors is an integer number (12763101).

Almost surely, 2^42543665 is an apocalyptic number.

It is an amenable number.

42543665 is a deficient number, since it is larger than the sum of its proper divisors (8508739).

42543665 is an equidigital number, since it uses as much as digits as its factorization.

42543665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8508738.

The product of its digits is 86400, while the sum is 35.

The square root of 42543665 is about 6522.5504980797. The cubic root of 42543665 is about 349.0960756610.

The spelling of 42543665 in words is "forty-two million, five hundred forty-three thousand, six hundred sixty-five".