31211220212 has 6 divisors (see below), whose sum is σ = 54619635378. Its totient is φ = 15605610104.

The previous prime is 31211220211. The next prime is 31211220251. The reversal of 31211220212 is 21202211213.

It can be written as a sum of positive squares in only one way, i.e., 29225270116 + 1985950096 = 170954^2 + 44564^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31211220211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3901402523 + ... + 3901402530.

It is an arithmetic number, because the mean of its divisors is an integer number (9103272563).

Almost surely, 2^31211220212 is an apocalyptic number.

It is an amenable number.

31211220212 is a deficient number, since it is larger than the sum of its proper divisors (23408415166).

31211220212 is a wasteful number, since it uses less digits than its factorization.

31211220212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7802805057 (or 7802805055 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 31211220212 its reverse (21202211213), we get a palindrome (52413431425).

The spelling of 31211220212 in words is "thirty-one billion, two hundred eleven million, two hundred twenty thousand, two hundred twelve".