21101221100 has 36 divisors (see below), whose sum is σ = 48483162504. Its totient is φ = 7943988480.

The previous prime is 21101221021. The next prime is 21101221103. The reversal of 21101221100 is 112210112.

It is a super-2 number, since 2×21101221100² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21101221103) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 6204542 + ... + 6207941.

It is an arithmetic number, because the mean of its divisors is an integer number (1346754514).

Almost surely, 2^21101221100 is an apocalyptic number.

21101221100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101221100 is an abundant number, since it is smaller than the sum of its proper divisors (27381941404).

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

21101221100 is a wasteful number, since it uses less digits than its factorization.

21101221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12412514 (or 12412507 counting only the distinct ones).

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

Adding to 21101221100 its reverse (112210112), we get a palindrome (21213431212).

The spelling of 21101221100 in words is "twenty-one billion, one hundred one million, two hundred twenty-one thousand, one hundred".