31431145 has 4 divisors (see below), whose sum is σ = 37717380. Its totient is φ = 25144912.

The previous prime is 31431139. The next prime is 31431161. The reversal of 31431145 is 54113413.

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 22857961 + 8573184 = 4781^2 + 2928^2 .

It is a cyclic number.

It is not a de Polignac number, because 31431145 - 2³ = 31431137 is a prime.

It is a super-2 number, since 2×31431145² = 1975833752022050, which contains 22 as substring.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 3143110 + ... + 3143119.

It is an arithmetic number, because the mean of its divisors is an integer number (9429345).

Almost surely, 2^31431145 is an apocalyptic number.

It is an amenable number.

31431145 is a deficient number, since it is larger than the sum of its proper divisors (6286235).

31431145 is an equidigital number, since it uses as much as digits as its factorization.

31431145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6286234.

The product of its digits is 720, while the sum is 22.

The square root of 31431145 is about 5606.3486334690. The cubic root of 31431145 is about 315.5876993465.

Adding to 31431145 its reverse (54113413), we get a palindrome (85544558).

The spelling of 31431145 in words is "thirty-one million, four hundred thirty-one thousand, one hundred forty-five".