21201220000000 has 144 divisors (see below), whose sum is σ = 52899442897392. Its totient is φ = 8480480000000.

The previous prime is 21201219999991. The next prime is 21201220000021. The reversal of 21201220000000 is 2210212.

It can be written as a sum of positive squares in 8 ways, for example, as 12328637798656 + 8872582201344 = 3511216^2 + 2978688^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 19469970 + ... + 20530030.

It is an arithmetic number, because the mean of its divisors is an integer number (367357242343).

Almost surely, 2^{21201220000000} is an apocalyptic number.

21201220000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21201220000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26449721448696).

21201220000000 is an abundant number, since it is smaller than the sum of its proper divisors (31698222897392).

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

21201220000000 is an frugal number, since it uses more digits than its factorization.

21201220000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060112 (or 1060068 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21201220000000 its reverse (2210212), we get a palindrome (21201222210212).

The spelling of 21201220000000 in words is "twenty-one trillion, two hundred one billion, two hundred twenty million", and thus it is an aban number.