31009212 has 72 divisors (see below), whose sum is σ = 85123584. Its totient is φ = 9461376.

The previous prime is 31009211. The next prime is 31009213. The reversal of 31009212 is 21290013.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (31009211) and next prime (31009213).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31009211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80773 + ... + 81155.

It is an arithmetic number, because the mean of its divisors is an integer number (1182272).

Almost surely, 2^31009212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31009212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42561792).

31009212 is an abundant number, since it is smaller than the sum of its proper divisors (54114372).

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

31009212 is a wasteful number, since it uses less digits than its factorization.

31009212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579 (or 574 counting only the distinct ones).

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

The square root of 31009212 is about 5568.5915634027. The cubic root of 31009212 is about 314.1691787150.

Adding to 31009212 its reverse (21290013), we get a palindrome (52299225).

The spelling of 31009212 in words is "thirty-one million, nine thousand, two hundred twelve".