21121201100 has 18 divisors (see below), whose sum is σ = 45833006604. Its totient is φ = 8448480400.

The previous prime is 21121201099. The next prime is 21121201109. The reversal of 21121201100 is 110212112.

It is a super-2 number, since 2×21121201100² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121201109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105605906 + ... + 105606105.

Almost surely, 2^21121201100 is an apocalyptic number.

21121201100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121201100 is an abundant number, since it is smaller than the sum of its proper divisors (24711805504).

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

21121201100 is a wasteful number, since it uses less digits than its factorization.

21121201100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211212025 (or 211212018 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21121201100 its reverse (110212112), we get a palindrome (21231413212).

The spelling of 21121201100 in words is "twenty-one billion, one hundred twenty-one million, two hundred one thousand, one hundred".