31213225 has 6 divisors (see below), whose sum is σ = 38704430. Its totient is φ = 24970560.

The previous prime is 31213213. The next prime is 31213243. The reversal of 31213225 is 52231213.

It can be written as a sum of positive squares in 3 ways, for example, as 266256 + 30946969 = 516^2 + 5563^2 .

It is not a de Polignac number, because 31213225 - 2¹⁷ = 31082153 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 624240 + ... + 624289.

Almost surely, 2^31213225 is an apocalyptic number.

It is an amenable number.

31213225 is a deficient number, since it is larger than the sum of its proper divisors (7491205).

31213225 is a wasteful number, since it uses less digits than its factorization.

31213225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1248539 (or 1248534 counting only the distinct ones).

The product of its digits is 360, while the sum is 19.

The square root of 31213225 is about 5586.8797194856. The cubic root of 31213225 is about 314.8566577174.

Adding to 31213225 its reverse (52231213), we get a palindrome (83444438).

The spelling of 31213225 in words is "thirty-one million, two hundred thirteen thousand, two hundred twenty-five".