31440042 has 16 divisors (see below), whose sum is σ = 69866880. Its totient is φ = 10479996.

The previous prime is 31440001. The next prime is 31440049. The reversal of 31440042 is 24004413.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31439997 and 31440024.

It is not an unprimeable number, because it can be changed into a prime (31440049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291058 + ... + 291165.

It is an arithmetic number, because the mean of its divisors is an integer number (4366680).

Almost surely, 2^31440042 is an apocalyptic number.

31440042 is an abundant number, since it is smaller than the sum of its proper divisors (38426838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31440042 is a wasteful number, since it uses less digits than its factorization.

31440042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582234 (or 582228 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 31440042 is about 5607.1420527752. The cubic root of 31440042 is about 315.6174736237.

Adding to 31440042 its reverse (24004413), we get a palindrome (55444455).

The spelling of 31440042 in words is "thirty-one million, four hundred forty thousand, forty-two".