31440405 has 16 divisors (see below), whose sum is σ = 50439744. Its totient is φ = 16723200.

The previous prime is 31440403. The next prime is 31440413. The reversal of 31440405 is 50404413.

It is not a de Polignac number, because 31440405 - 2¹ = 31440403 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31440401) 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 15 ways as a sum of consecutive naturals, for example, 3402 + ... + 8628.

It is an arithmetic number, because the mean of its divisors is an integer number (3152484).

Almost surely, 2^31440405 is an apocalyptic number.

It is an amenable number.

31440405 is a deficient number, since it is larger than the sum of its proper divisors (18999339).

31440405 is a wasteful number, since it uses less digits than its factorization.

31440405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5636.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 31440405 is about 5607.1744221132. The cubic root of 31440405 is about 315.6186883030.

Adding to 31440405 its reverse (50404413), we get a palindrome (81844818).

The spelling of 31440405 in words is "thirty-one million, four hundred forty thousand, four hundred five".