21121121221100 has 72 divisors (see below), whose sum is σ = 45859987356288. Its totient is φ = 8443444838400.

The previous prime is 21121121221049. The next prime is 21121121221121. The reversal of 21121121221100 is 112212112112.

It is a super-2 number, since 2×21121121221100² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1499966060 + ... + 1499980140.

Almost surely, 2^{21121121221100} is an apocalyptic number.

21121121221100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121121221100 is an abundant number, since it is smaller than the sum of its proper divisors (24738866135188).

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

21121121221100 is a wasteful number, since it uses less digits than its factorization.

21121121221100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21915 (or 21908 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21121121221100 its reverse (112212112112), we get a palindrome (21233333333212).

The spelling of 21121121221100 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred".