31212009 has 12 divisors (see below), whose sum is σ = 46538752. Its totient is φ = 20136600.

The previous prime is 31212001. The next prime is 31212037. The reversal of 31212009 is 90021213.

It is a happy number.

It is not a de Polignac number, because 31212009 - 2³ = 31212001 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31211982 and 31212000.

It is not an unprimeable number, because it can be changed into a prime (31212001) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 55657 + ... + 56214.

Almost surely, 2^31212009 is an apocalyptic number.

It is an amenable number.

31212009 is a deficient number, since it is larger than the sum of its proper divisors (15326743).

31212009 is a wasteful number, since it uses less digits than its factorization.

31212009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111908 (or 111905 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 31212009 is about 5586.7708920270. The cubic root of 31212009 is about 314.8525689519.

It can be divided in two parts, 312 and 12009, that added together give a palindrome (12321).

The spelling of 31212009 in words is "thirty-one million, two hundred twelve thousand, nine".