31021220312 has 8 divisors (see below), whose sum is σ = 58164788100. Its totient is φ = 15510610152.

The previous prime is 31021220297. The next prime is 31021220317. The reversal of 31021220312 is 21302212013.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×31021220312² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31021220317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1938826262 + ... + 1938826277.

Almost surely, 2^31021220312 is an apocalyptic number.

It is an amenable number.

31021220312 is a deficient number, since it is larger than the sum of its proper divisors (27143567788).

31021220312 is a wasteful number, since it uses less digits than its factorization.

31021220312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3877652545 (or 3877652541 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 31021220312 its reverse (21302212013), we get a palindrome (52323432325).

The spelling of 31021220312 in words is "thirty-one billion, twenty-one million, two hundred twenty thousand, three hundred twelve".