21211212100000 has 144 divisors (see below), whose sum is σ = 56211216611256. Its totient is φ = 7831831680000.

The previous prime is 21211212099983. The next prime is 21211212100019. The reversal of 21211212100000 is 121211212.

It can be written as a sum of positive squares in 12 ways, for example, as 17530600545936 + 3680611554064 = 4186956^2 + 1918492^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6858159 + ... + 9458158.

Almost surely, 2^{21211212100000} is an apocalyptic number.

21211212100000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211212100000 is an abundant number, since it is smaller than the sum of its proper divisors (35000004511256).

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

21211212100000 is an equidigital number, since it uses as much as digits as its factorization.

21211212100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16316365 (or 16316337 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21211212100000 its reverse (121211212), we get a palindrome (21211333311212).

The spelling of 21211212100000 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, one hundred thousand".