21120012312 has 128 divisors (see below), whose sum is σ = 61382400000. Its totient is φ = 5931035136.

The previous prime is 21120012307. The next prime is 21120012317. The reversal of 21120012312 is 21321002112.

It is an interprime number because it is at equal distance from previous prime (21120012307) and next prime (21120012317).

It is a junction number, because it is equal to n+sod(n) for n = 21120012291 and 21120012300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120012317) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3035814 + ... + 3042762.

It is an arithmetic number, because the mean of its divisors is an integer number (479550000).

Almost surely, 2^21120012312 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 21120012312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30691200000).

21120012312 is an abundant number, since it is smaller than the sum of its proper divisors (40262387688).

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

21120012312 is a wasteful number, since it uses less digits than its factorization.

21120012312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7273 (or 7269 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21120012312 its reverse (21321002112), we get a palindrome (42441014424).

The spelling of 21120012312 in words is "twenty-one billion, one hundred twenty million, twelve thousand, three hundred twelve".