21121121100 has 72 divisors (see below), whose sum is σ = 61400250688. Its totient is φ = 5605588800.

The previous prime is 21121121089. The next prime is 21121121101. The reversal of 21121121100 is 112112112.

It is a super-2 number, since 2×21121121100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21121121101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 103534 + ... + 230133.

Almost surely, 2^21121121100 is an apocalyptic number.

21121121100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121121100 is an abundant number, since it is smaller than the sum of its proper divisors (40279129588).

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

21121121100 is a wasteful number, since it uses less digits than its factorization.

21121121100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333895 (or 333888 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21121121100 its reverse (112112112), we get a palindrome (21233233212).

It can be divided in two parts, 21 and 121121100, that added together give a palindrome (121121121).

The spelling of 21121121100 in words is "twenty-one billion, one hundred twenty-one million, one hundred twenty-one thousand, one hundred".