21201212201100 has 144 divisors (see below), whose sum is σ = 62662780992000. Its totient is φ = 5532001009920.

The previous prime is 21201212201089. The next prime is 21201212201111. The reversal of 21201212201100 is 110221210212.

It is an interprime number because it is at equal distance from previous prime (21201212201089) and next prime (21201212201111).

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 21201212201100.

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 47 ways as a sum of consecutive naturals, for example, 57612486 + ... + 57979314.

Almost surely, 2^{21201212201100} is an apocalyptic number.

21201212201100 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 21201212201100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31331390496000).

21201212201100 is an abundant number, since it is smaller than the sum of its proper divisors (41461568790900).

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

21201212201100 is a wasteful number, since it uses less digits than its factorization.

21201212201100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370992 (or 370985 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201212201100 its reverse (110221210212), we get a palindrome (21311433411312).

The spelling of 21201212201100 in words is "twenty-one trillion, two hundred one billion, two hundred twelve million, two hundred one thousand, one hundred".