31406405 has 4 divisors (see below), whose sum is σ = 37687692. Its totient is φ = 25125120.

The previous prime is 31406393. The next prime is 31406423. The reversal of 31406405 is 50460413.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13147876 + 18258529 = 3626^2 + 4273^2 .

It is not a de Polignac number, because 31406405 - 2¹² = 31402309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3140636 + ... + 3140645.

It is an arithmetic number, because the mean of its divisors is an integer number (9421923).

Almost surely, 2^31406405 is an apocalyptic number.

It is an amenable number.

31406405 is a deficient number, since it is larger than the sum of its proper divisors (6281287).

31406405 is an equidigital number, since it uses as much as digits as its factorization.

31406405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6281286.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 31406405 is about 5604.1417719397. The cubic root of 31406405 is about 315.5048760928.

Adding to 31406405 its reverse (50460413), we get a palindrome (81866818).

The spelling of 31406405 in words is "thirty-one million, four hundred six thousand, four hundred five".