42172845 has 32 divisors (see below), whose sum is σ = 79277184. Its totient is φ = 18873600.

The previous prime is 42172841. The next prime is 42172849. The reversal of 42172845 is 54827124.

It is an interprime number because it is at equal distance from previous prime (42172841) and next prime (42172849).

It is not a de Polignac number, because 42172845 - 2² = 42172841 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42172841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7686 + ... + 11975.

It is an arithmetic number, because the mean of its divisors is an integer number (2477412).

Almost surely, 2^42172845 is an apocalyptic number.

It is an amenable number.

42172845 is a deficient number, since it is larger than the sum of its proper divisors (37104339).

42172845 is a wasteful number, since it uses less digits than its factorization.

42172845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19693.

The product of its digits is 17920, while the sum is 33.

The square root of 42172845 is about 6494.0622879674. The cubic root of 42172845 is about 348.0788482321.

Adding to 42172845 its reverse (54827124), we get a palindrome (96999969).

The spelling of 42172845 in words is "forty-two million, one hundred seventy-two thousand, eight hundred forty-five".