21120012020040 has 128 divisors (see below), whose sum is σ = 63557188168320. Its totient is φ = 5614481664000.

The previous prime is 21120012020039. The next prime is 21120012020047. The reversal of 21120012020040 is 4002021002112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (21120012020047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 691152442 + ... + 691182998.

It is an arithmetic number, because the mean of its divisors is an integer number (496540532565).

Almost surely, 2^{21120012020040} is an apocalyptic number.

21120012020040 is a gapful number since it is divisible by the number (20) 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 21120012020040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31778594084160).

21120012020040 is an abundant number, since it is smaller than the sum of its proper divisors (42437176148280).

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

21120012020040 is a wasteful number, since it uses less digits than its factorization.

21120012020040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48303 (or 48299 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21120012020040 its reverse (4002021002112), we get a palindrome (25122033022152).

The spelling of 21120012020040 in words is "twenty-one trillion, one hundred twenty billion, twelve million, twenty thousand, forty".