21120020010 has 96 divisors (see below), whose sum is σ = 55715325120. Its totient is φ = 5550223104.

The previous prime is 21120019961. The next prime is 21120020029. The reversal of 21120020010 is 1002002112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21120019974 and 21120020001.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1707709 + ... + 1720031.

It is an arithmetic number, because the mean of its divisors is an integer number (580367970).

Almost surely, 2^21120020010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120020010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27857662560).

21120020010 is an abundant number, since it is smaller than the sum of its proper divisors (34595305110).

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

21120020010 is a wasteful number, since it uses less digits than its factorization.

21120020010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12612 (or 12609 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21120020010 its reverse (1002002112), we get a palindrome (22122022122).

The spelling of 21120020010 in words is "twenty-one billion, one hundred twenty million, twenty thousand, ten".