21211221300 has 144 divisors (see below), whose sum is σ = 65054086272. Its totient is φ = 5317632000.

The previous prime is 21211221277. The next prime is 21211221313. The reversal of 21211221300 is 312211212.

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 21211221300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6123369 + ... + 6126831.

It is an arithmetic number, because the mean of its divisors is an integer number (451764488).

Almost surely, 2^21211221300 is an apocalyptic number.

21211221300 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 21211221300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32527043136).

21211221300 is an abundant number, since it is smaller than the sum of its proper divisors (43842864972).

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

21211221300 is a wasteful number, since it uses less digits than its factorization.

21211221300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4698 (or 4691 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21211221300 its reverse (312211212), we get a palindrome (21523432512).

The spelling of 21211221300 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, three hundred".