21211111200120 has 64 divisors (see below), whose sum is σ = 63635798016000. Its totient is φ = 5656077260928.

The previous prime is 21211111200101. The next prime is 21211111200137. The reversal of 21211111200120 is 2100211111212.

It is a happy number.

It is a super-2 number, since 2×21211111200120² (a number of 27 digits) contains 22 as substring.

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 21211111200120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 299560 + ... + 6520119.

It is an arithmetic number, because the mean of its divisors is an integer number (994309344000).

Almost surely, 2^{21211111200120} is an apocalyptic number.

21211111200120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211111200120 is an abundant number, since it is smaller than the sum of its proper divisors (42424686815880).

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

21211111200120 is a wasteful number, since it uses less digits than its factorization.

21211111200120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6845612 (or 6845608 counting only the distinct ones).

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

Adding to 21211111200120 its reverse (2100211111212), we get a palindrome (23311322311332).

The spelling of 21211111200120 in words is "twenty-one trillion, two hundred eleven billion, one hundred eleven million, two hundred thousand, one hundred twenty".