21310440012 has 84 divisors (see below), whose sum is σ = 56002565640. Its totient is φ = 7092271872.

The previous prime is 21310440001. The next prime is 21310440013. The reversal of 21310440012 is 21004401312.

21310440012 is a `hidden beast` number, since 213 + 1 + 0 + 440 + 0 + 12 = 666.

It is a super-3 number, since 3×21310440012³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310440013) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 1957039 + ... + 1967897.

It is an arithmetic number, because the mean of its divisors is an integer number (666697210).

Almost surely, 2^21310440012 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 21310440012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28001282820).

21310440012 is an abundant number, since it is smaller than the sum of its proper divisors (34692125628).

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

21310440012 is a wasteful number, since it uses less digits than its factorization.

21310440012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11554 (or 11537 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21310440012 its reverse (21004401312), we get a palindrome (42314841324).

It can be divided in two parts, 213104 and 40012, that added together give a triangular number (253116 = T₇₁₁).

The spelling of 21310440012 in words is "twenty-one billion, three hundred ten million, four hundred forty thousand, twelve".