21212200202120 has 64 divisors (see below), whose sum is σ = 48525732480240. Its totient is φ = 8343054259200.

The previous prime is 21212200202101. The next prime is 21212200202131. The reversal of 21212200202120 is 2120200221212.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 2464391346244 + 18747808855876 = 1569838^2 + 4329874^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6048794 + ... + 8888886.

Almost surely, 2^{21212200202120} is an apocalyptic number.

21212200202120 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 21212200202120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24262866240120).

21212200202120 is an abundant number, since it is smaller than the sum of its proper divisors (27313532278120).

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

21212200202120 is a wasteful number, since it uses less digits than its factorization.

21212200202120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843226 (or 2843222 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21212200202120 its reverse (2120200221212), we get a palindrome (23332400423332).

The spelling of 21212200202120 in words is "twenty-one trillion, two hundred twelve billion, two hundred million, two hundred two thousand, one hundred twenty".