21120045012 has 72 divisors (see below), whose sum is σ = 58321029312. Its totient is φ = 6391123200.

The previous prime is 21120045007. The next prime is 21120045019. The reversal of 21120045012 is 21054002112.

21120045012 is a `hidden beast` number, since 2 + 1 + 1 + 200 + 450 + 12 = 666.

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 (21120045019) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 251212 + ... + 324572.

It is an arithmetic number, because the mean of its divisors is an integer number (810014296).

Almost surely, 2^21120045012 is an apocalyptic number.

21120045012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120045012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29160514656).

21120045012 is an abundant number, since it is smaller than the sum of its proper divisors (37200984300).

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

21120045012 is a wasteful number, since it uses less digits than its factorization.

21120045012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74109 (or 74104 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21120045012 its reverse (21054002112), we get a palindrome (42174047124).

The spelling of 21120045012 in words is "twenty-one billion, one hundred twenty million, forty-five thousand, twelve".