31320221212 has 72 divisors (see below), whose sum is σ = 66204250560. Its totient is φ = 12911633280.

The previous prime is 31320221173. The next prime is 31320221221. The reversal of 31320221212 is 21212202313.

It is a super-2 number, since 2×31320221212² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31320221212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1530198 + ... + 1550530.

It is an arithmetic number, because the mean of its divisors is an integer number (919503480).

Almost surely, 2^31320221212 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 31320221212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33102125280).

31320221212 is an abundant number, since it is smaller than the sum of its proper divisors (34884029348).

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

31320221212 is a wasteful number, since it uses less digits than its factorization.

31320221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20651 (or 20642 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 31320221212 its reverse (21212202313), we get a palindrome (52532423525).

The spelling of 31320221212 in words is "thirty-one billion, three hundred twenty million, two hundred twenty-one thousand, two hundred twelve".