21111011100 has 144 divisors (see below), whose sum is σ = 70208527200. Its totient is φ = 5435458560.

The previous prime is 21111011099. The next prime is 21111011107. The reversal of 21111011100 is 111011112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111011107) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 56509 + ... + 213108.

Almost surely, 2^21111011100 is an apocalyptic number.

21111011100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111011100 is an abundant number, since it is smaller than the sum of its proper divisors (49097516100).

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

21111011100 is a wasteful number, since it uses less digits than its factorization.

21111011100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269669 (or 269656 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21111011100 its reverse (111011112), we get a palindrome (21222022212).

The spelling of 21111011100 in words is "twenty-one billion, one hundred eleven million, eleven thousand, one hundred".