21201111100 has 36 divisors (see below), whose sum is σ = 49545368824. Its totient is φ = 7828102080.

The previous prime is 21201111089. The next prime is 21201111101. The reversal of 21201111100 is 111110212.

It is a super-2 number, since 2×21201111100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201111101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8152974 + ... + 8155573.

Almost surely, 2^21201111100 is an apocalyptic number.

21201111100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201111100 is an abundant number, since it is smaller than the sum of its proper divisors (28344257724).

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

21201111100 is a wasteful number, since it uses less digits than its factorization.

21201111100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16308574 (or 16308567 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21201111100 its reverse (111110212), we get a palindrome (21312221312).

The spelling of 21201111100 in words is "twenty-one billion, two hundred one million, one hundred eleven thousand, one hundred".