21021121211100 has 36 divisors (see below), whose sum is σ = 60821110704984. Its totient is φ = 5605632322880.

The previous prime is 21021121211071. The next prime is 21021121211119. The reversal of 21021121211100 is 111212112012.

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 21021121211100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35035201719 + ... + 35035202318.

Almost surely, 2^{21021121211100} is an apocalyptic number.

21021121211100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021121211100 is an abundant number, since it is smaller than the sum of its proper divisors (39799989493884).

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

21021121211100 is a wasteful number, since it uses less digits than its factorization.

21021121211100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70070404054 (or 70070404047 counting only the distinct ones).

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

Adding to 21021121211100 its reverse (111212112012), we get a palindrome (21132333323112).

It can be divided in two parts, 21021 and 121211100, that added together give a palindrome (121232121).

The spelling of 21021121211100 in words is "twenty-one trillion, twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, one hundred".