21211101212100 has 144 divisors (see below), whose sum is σ = 61732361334336. Its totient is φ = 5623050240000.

The previous prime is 21211101212099. The next prime is 21211101212111. The reversal of 21211101212100 is 121210111212.

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 21211101212100.

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, 41462875 + ... + 41971325.

Almost surely, 2^{21211101212100} is an apocalyptic number.

21211101212100 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 21211101212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30866180667168).

21211101212100 is an abundant number, since it is smaller than the sum of its proper divisors (40521260122236).

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

21211101212100 is a wasteful number, since it uses less digits than its factorization.

21211101212100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509286 (or 509279 counting only the distinct ones).

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

Adding to 21211101212100 its reverse (121210111212), we get a palindrome (21332311323312).

The spelling of 21211101212100 in words is "twenty-one trillion, two hundred eleven billion, one hundred one million, two hundred twelve thousand, one hundred".