21212121111000 has 128 divisors (see below), whose sum is σ = 66184943348160. Its totient is φ = 5656298496000.

The previous prime is 21212121110981. The next prime is 21212121111059. The reversal of 21212121111000 is 11112121212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 68007402 + ... + 68318598.

Almost surely, 2^{21212121111000} is an apocalyptic number.

21212121111000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212121111000 is an abundant number, since it is smaller than the sum of its proper divisors (44972822237160).

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

21212121111000 is a wasteful number, since it uses less digits than its factorization.

21212121111000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333942 (or 333928 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21212121111000 its reverse (11112121212), we get a palindrome (21223233232212).

The spelling of 21212121111000 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-one million, one hundred eleven thousand".