21002120260 has 96 divisors (see below), whose sum is σ = 49854268800. Its totient is φ = 7365795840.

The previous prime is 21002120257. The next prime is 21002120261. The reversal of 21002120260 is 6202120012.

It is not an unprimeable number, because it can be changed into a prime (21002120261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 672676 + ... + 703204.

It is an arithmetic number, because the mean of its divisors is an integer number (519315300).

Almost surely, 2^21002120260 is an apocalyptic number.

21002120260 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 21002120260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24927134400).

21002120260 is an abundant number, since it is smaller than the sum of its proper divisors (28852148540).

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

21002120260 is a wasteful number, since it uses less digits than its factorization.

21002120260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30661 (or 30659 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21002120260 its reverse (6202120012), we get a palindrome (27204240272).

The spelling of 21002120260 in words is "twenty-one billion, two million, one hundred twenty thousand, two hundred sixty".