42128939 has 4 divisors (see below), whose sum is σ = 43960656. Its totient is φ = 40297224.

The previous prime is 42128929. The next prime is 42128971. The reversal of 42128939 is 93982124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 42128939 - 2²⁴ = 25351723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42128929) 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, 915824 + ... + 915869.

It is an arithmetic number, because the mean of its divisors is an integer number (10990164).

Almost surely, 2^42128939 is an apocalyptic number.

42128939 is a deficient number, since it is larger than the sum of its proper divisors (1831717).

42128939 is a wasteful number, since it uses less digits than its factorization.

42128939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1831716.

The product of its digits is 31104, while the sum is 38.

The square root of 42128939 is about 6490.6809350021. The cubic root of 42128939 is about 347.9580117351.

The spelling of 42128939 in words is "forty-two million, one hundred twenty-eight thousand, nine hundred thirty-nine".