21001111100 has 36 divisors (see below), whose sum is σ = 46042251024. Its totient is φ = 8313838080.

The previous prime is 21001111081. The next prime is 21001111181. The reversal of 21001111100 is 111110012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 1072832 + ... + 1092231.

Almost surely, 2^21001111100 is an apocalyptic number.

21001111100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001111100 is an abundant number, since it is smaller than the sum of its proper divisors (25041139924).

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

21001111100 is a wasteful number, since it uses less digits than its factorization.

21001111100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2165174 (or 2165167 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 21001111100 its reverse (111110012), we get a palindrome (21112221112).

The spelling of 21001111100 in words is "twenty-one billion, one million, one hundred eleven thousand, one hundred".