42181931 has 18 divisors (see below), whose sum is σ = 48542340. Its totient is φ = 36624280.

The previous prime is 42181903. The next prime is 42181939. The reversal of 42181931 is 13918124.

It is not a de Polignac number, because 42181931 - 2¹⁰ = 42180907 is a prime.

It is a super-2 number, since 2×42181931² = 3558630605777522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 42181894 and 42181903.

It is not an unprimeable number, because it can be changed into a prime (42181939) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 63680 + ... + 64338.

Almost surely, 2^42181931 is an apocalyptic number.

42181931 is a deficient number, since it is larger than the sum of its proper divisors (6360409).

42181931 is a wasteful number, since it uses less digits than its factorization.

42181931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727 (or 693 counting only the distinct ones).

The product of its digits is 1728, while the sum is 29.

The square root of 42181931 is about 6494.7618124147. The cubic root of 42181931 is about 348.1038439161.

The spelling of 42181931 in words is "forty-two million, one hundred eighty-one thousand, nine hundred thirty-one".