42172161 has 4 divisors (see below), whose sum is σ = 56229552. Its totient is φ = 28114772.

The previous prime is 42172157. The next prime is 42172171. The reversal of 42172161 is 16127124.

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 a cyclic number.

It is not a de Polignac number, because 42172161 - 2² = 42172157 is a prime.

It is not an unprimeable number, because it can be changed into a prime (42172111) 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, 7028691 + ... + 7028696.

It is an arithmetic number, because the mean of its divisors is an integer number (14057388).

Almost surely, 2^42172161 is an apocalyptic number.

It is an amenable number.

42172161 is a deficient number, since it is larger than the sum of its proper divisors (14057391).

42172161 is a wasteful number, since it uses less digits than its factorization.

42172161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14057390.

The product of its digits is 672, while the sum is 24.

The square root of 42172161 is about 6494.0096242614. The cubic root of 42172161 is about 348.0769663955.

Adding to 42172161 its reverse (16127124), we get a palindrome (58299285).

The spelling of 42172161 in words is "forty-two million, one hundred seventy-two thousand, one hundred sixty-one".