21210120001220 has 48 divisors (see below), whose sum is σ = 44607267392688. Its totient is φ = 8471474995200.

The previous prime is 21210120001117. The next prime is 21210120001349. The reversal of 21210120001220 is 2210002101212.

It can be written as a sum of positive squares in 8 ways, for example, as 5850477338176 + 15359642663044 = 2418776^2 + 3919138^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21210120001195 and 21210120001204.

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, 366972644 + ... + 367030436.

It is an arithmetic number, because the mean of its divisors is an integer number (929318070681).

Almost surely, 2^{21210120001220} is an apocalyptic number.

21210120001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210120001220 is an abundant number, since it is smaller than the sum of its proper divisors (23397147391468).

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

21210120001220 is a wasteful number, since it uses less digits than its factorization.

21210120001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84680 (or 84678 counting only the distinct ones).

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

Adding to 21210120001220 its reverse (2210002101212), we get a palindrome (23420122102432).

The spelling of 21210120001220 in words is "twenty-one trillion, two hundred ten billion, one hundred twenty million, one thousand, two hundred twenty".