21000111100 has 18 divisors (see below), whose sum is σ = 45570241304. Its totient is φ = 8400044400.

The previous prime is 21000111091. The next prime is 21000111113. The reversal of 21000111100 is 111100012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105000456 + ... + 105000655.

Almost surely, 2^21000111100 is an apocalyptic number.

21000111100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000111100 is an abundant number, since it is smaller than the sum of its proper divisors (24570130204).

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

21000111100 is a wasteful number, since it uses less digits than its factorization.

21000111100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210001125 (or 210001118 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 7.

Adding to 21000111100 its reverse (111100012), we get a palindrome (21111211112).

The spelling of 21000111100 in words is "twenty-one billion, one hundred eleven thousand, one hundred".