21001111210120 has 32 divisors (see below), whose sum is σ = 47279091547800. Its totient is φ = 8395717137408.

The previous prime is 21001111210111. The next prime is 21001111210147. The reversal of 21001111210120 is 2101211110012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18809343476676 + 2191767733444 = 4336974^2 + 1480462^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21001111210120.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147657615 + ... + 147799774.

Almost surely, 2^{21001111210120} is an apocalyptic number.

21001111210120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001111210120 is an abundant number, since it is smaller than the sum of its proper divisors (26277980337680).

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

21001111210120 is a wasteful number, since it uses less digits than its factorization.

21001111210120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295459177 (or 295459173 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21001111210120 its reverse (2101211110012), we get a palindrome (23102322320132).

The spelling of 21001111210120 in words is "twenty-one trillion, one billion, one hundred eleven million, two hundred ten thousand, one hundred twenty".