42172261 has 4 divisors (see below), whose sum is σ = 42196012. Its totient is φ = 42148512.

The previous prime is 42172219. The next prime is 42172297. The reversal of 42172261 is 16227124.

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 28622500 + 13549761 = 5350^2 + 3681^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42172261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42172201) 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, 8976 + ... + 12841.

It is an arithmetic number, because the mean of its divisors is an integer number (10549003).

Almost surely, 2^42172261 is an apocalyptic number.

It is an amenable number.

42172261 is a deficient number, since it is larger than the sum of its proper divisors (23751).

42172261 is a wasteful number, since it uses less digits than its factorization.

42172261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23750.

The product of its digits is 1344, while the sum is 25.

The square root of 42172261 is about 6494.0173236603. The cubic root of 42172261 is about 348.0772415191.

Adding to 42172261 its reverse (16227124), we get a palindrome (58399385).

The spelling of 42172261 in words is "forty-two million, one hundred seventy-two thousand, two hundred sixty-one".