21031020312 has 64 divisors (see below), whose sum is σ = 54044016480. Its totient is φ = 6817155072.

The previous prime is 21031020287. The next prime is 21031020317. The reversal of 21031020312 is 21302013012.

It is a junction number, because it is equal to n+sod(n) for n = 21031020291 and 21031020300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031020317) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70578 + ... + 216894.

Almost surely, 2^21031020312 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 21031020312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27022008240).

21031020312 is an abundant number, since it is smaller than the sum of its proper divisors (33012996168).

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

21031020312 is a wasteful number, since it uses less digits than its factorization.

21031020312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146492 (or 146488 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21031020312 its reverse (21302013012), we get a palindrome (42333033324).

The spelling of 21031020312 in words is "twenty-one billion, thirty-one million, twenty thousand, three hundred twelve".