31212221312 has 16 divisors (see below), whose sum is σ = 62180597400. Its totient is φ = 15606110592.

The previous prime is 31212221309. The next prime is 31212221347. The reversal of 31212221312 is 21312221213.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121922612 + ... + 121922867.

Almost surely, 2^31212221312 is an apocalyptic number.

31212221312 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

31212221312 is a deficient number, since it is larger than the sum of its proper divisors (30968376088).

31212221312 is an equidigital number, since it uses as much as digits as its factorization.

31212221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243845493 (or 243845481 counting only the distinct ones).

The product of its digits is 288, while the sum is 20.

Adding to 31212221312 its reverse (21312221213), we get a palindrome (52524442525).

Subtracting from 31212221312 its reverse (21312221213), we obtain a palindrome (9900000099).

The spelling of 31212221312 in words is "thirty-one billion, two hundred twelve million, two hundred twenty-one thousand, three hundred twelve".