31213206 has 12 divisors (see below), whose sum is σ = 67628652. Its totient is φ = 10404396.

The previous prime is 31213201. The next prime is 31213211. The reversal of 31213206 is 60231213.

It is an interprime number because it is at equal distance from previous prime (31213201) and next prime (31213211).

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1734067 = 31213206 / (3 + 1 + 2 + 1 + 3 + 2 + 0 + 6).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213201) 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 5 ways as a sum of consecutive naturals, for example, 867016 + ... + 867051.

It is an arithmetic number, because the mean of its divisors is an integer number (5635721).

Almost surely, 2^31213206 is an apocalyptic number.

31213206 is an abundant number, since it is smaller than the sum of its proper divisors (36415446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31213206 is a wasteful number, since it uses less digits than its factorization.

31213206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1734075 (or 1734072 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 31213206 is about 5586.8780190729. The cubic root of 31213206 is about 314.8565938312.

Adding to 31213206 its reverse (60231213), we get a palindrome (91444419).

The spelling of 31213206 in words is "thirty-one million, two hundred thirteen thousand, two hundred six".