21002121121110 has 32 divisors (see below), whose sum is σ = 50577121738080. Its totient is φ = 5581451071488.

The previous prime is 21002121121087. The next prime is 21002121121123. The reversal of 21002121121110 is 1112112120012.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21002121121110.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1194651115 + ... + 1194668694.

It is an arithmetic number, because the mean of its divisors is an integer number (1580535054315).

Almost surely, 2^{21002121121110} is an apocalyptic number.

21002121121110 is an abundant number, since it is smaller than the sum of its proper divisors (29575000616970).

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

21002121121110 is a wasteful number, since it uses less digits than its factorization.

21002121121110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2389320112.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21002121121110 its reverse (1112112120012), we get a palindrome (22114233241122).

The spelling of 21002121121110 in words is "twenty-one trillion, two billion, one hundred twenty-one million, one hundred twenty-one thousand, one hundred ten".