31212225 has 36 divisors (see below), whose sum is σ = 60991632. Its totient is φ = 15132000.

The previous prime is 31212197. The next prime is 31212227. The reversal of 31212225 is 52221213.

It is not a de Polignac number, because 31212225 - 2⁶ = 31212161 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31212198 and 31212207.

It is not an unprimeable number, because it can be changed into a prime (31212227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3831 + ... + 8780.

It is an arithmetic number, because the mean of its divisors is an integer number (1694212).

Almost surely, 2^31212225 is an apocalyptic number.

It is an amenable number.

31212225 is a deficient number, since it is larger than the sum of its proper divisors (29779407).

31212225 is a wasteful number, since it uses less digits than its factorization.

31212225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12638 (or 12630 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 31212225 is about 5586.7902233751. The cubic root of 31212225 is about 314.8532952535.

Adding to 31212225 its reverse (52221213), we get a palindrome (83433438).

The spelling of 31212225 in words is "thirty-one million, two hundred twelve thousand, two hundred twenty-five".