21111221100120 has 64 divisors (see below), whose sum is σ = 63334019305440. Its totient is φ = 5629627315200.

The previous prime is 21111221100103. The next prime is 21111221100121. The reversal of 21111221100120 is 2100112211112.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21111221100120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111221100121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27536380 + ... + 28292660.

Almost surely, 2^{21111221100120} is an apocalyptic number.

21111221100120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111221100120 is an abundant number, since it is smaller than the sum of its proper divisors (42222798205320).

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

21111221100120 is a wasteful number, since it uses less digits than its factorization.

21111221100120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 988916 (or 988912 counting only the distinct ones).

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

Adding to 21111221100120 its reverse (2100112211112), we get a palindrome (23211333311232).

The spelling of 21111221100120 in words is "twenty-one trillion, one hundred eleven billion, two hundred twenty-one million, one hundred thousand, one hundred twenty".