42181723 has 4 divisors (see below), whose sum is σ = 42263208. Its totient is φ = 42100240.

The previous prime is 42181721. The next prime is 42181757. The reversal of 42181723 is 32718124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 42181723 - 2¹ = 42181721 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42181691 and 42181700.

It is not an unprimeable number, because it can be changed into a prime (42181721) 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, 39961 + ... + 41002.

It is an arithmetic number, because the mean of its divisors is an integer number (10565802).

Almost surely, 2^42181723 is an apocalyptic number.

42181723 is a deficient number, since it is larger than the sum of its proper divisors (81485).

42181723 is an equidigital number, since it uses as much as digits as its factorization.

42181723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81484.

The product of its digits is 2688, while the sum is 28.

The square root of 42181723 is about 6494.7457994905. The cubic root of 42181723 is about 348.1032717460.

Adding to 42181723 its reverse (32718124), we get a palindrome (74899847).

The spelling of 42181723 in words is "forty-two million, one hundred eighty-one thousand, seven hundred twenty-three".