21212120210000 has 50 divisors (see below), whose sum is σ = 51356664264642. Its totient is φ = 8484848080000.

The previous prime is 21212120209939. The next prime is 21212120210023. The reversal of 21212120210000 is 1202121212.

It can be written as a sum of positive squares in 5 ways, for example, as 1759856947216 + 19452263262784 = 1326596^2 + 4410472^2 .

It is a tau number, because it is divible by the number of its divisors (50).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1060596011 + ... + 1060616010.

Almost surely, 2^{21212120210000} is an apocalyptic number.

21212120210000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212120210000 is an abundant number, since it is smaller than the sum of its proper divisors (30144544054642).

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

21212120210000 is an equidigital number, since it uses as much as digits as its factorization.

21212120210000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121212049 (or 2121212028 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21212120210000 its reverse (1202121212), we get a palindrome (21213322331212).

The spelling of 21212120210000 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty million, two hundred ten thousand".