42078731 has 4 divisors (see below), whose sum is σ = 43216032. Its totient is φ = 40941432.

The previous prime is 42078719. The next prime is 42078737. The reversal of 42078731 is 13787024.

It is a happy number.

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 42078731 - 2¹⁴ = 42062347 is a prime.

It is a super-2 number, since 2×42078731² = 3541239205140722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42078737) 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, 568595 + ... + 568668.

It is an arithmetic number, because the mean of its divisors is an integer number (10804008).

Almost surely, 2^42078731 is an apocalyptic number.

42078731 is a deficient number, since it is larger than the sum of its proper divisors (1137301).

42078731 is a wasteful number, since it uses less digits than its factorization.

42078731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1137300.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 42078731 is about 6486.8120829881. The cubic root of 42078731 is about 347.8197281621.

The spelling of 42078731 in words is "forty-two million, seventy-eight thousand, seven hundred thirty-one".