42638391 has 6 divisors (see below), whose sum is σ = 61588800. Its totient is φ = 28425588.

The previous prime is 42638371. The next prime is 42638417. The reversal of 42638391 is 19383624.

42638391 is a `hidden beast` number, since 4 + 263 + 8 + 391 = 666.

42638391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 42638391 - 2⁵ = 42638359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42638371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2368791 + ... + 2368808.

It is an arithmetic number, because the mean of its divisors is an integer number (10264800).

Almost surely, 2^42638391 is an apocalyptic number.

42638391 is a deficient number, since it is larger than the sum of its proper divisors (18950409).

42638391 is a wasteful number, since it uses less digits than its factorization.

42638391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4737605 (or 4737602 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 42638391 is about 6529.8078838508. The cubic root of 42638391 is about 349.3549779927.

The spelling of 42638391 in words is "forty-two million, six hundred thirty-eight thousand, three hundred ninety-one".