42171823 has 4 divisors (see below), whose sum is σ = 43311640. Its totient is φ = 41032008.

The previous prime is 42171809. The next prime is 42171853. The reversal of 42171823 is 32817124.

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 42171823 - 2⁵ = 42171791 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42171791 and 42171800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42171853) 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, 569853 + ... + 569926.

It is an arithmetic number, because the mean of its divisors is an integer number (10827910).

Almost surely, 2^42171823 is an apocalyptic number.

42171823 is a deficient number, since it is larger than the sum of its proper divisors (1139817).

42171823 is a wasteful number, since it uses less digits than its factorization.

42171823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1139816.

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

The square root of 42171823 is about 6493.9836002257. The cubic root of 42171823 is about 348.0760364745.

Adding to 42171823 its reverse (32817124), we get a palindrome (74988947).

The spelling of 42171823 in words is "forty-two million, one hundred seventy-one thousand, eight hundred twenty-three".