21221121210220 has 48 divisors (see below), whose sum is σ = 47234583950400. Its totient is φ = 7980866095104.

The previous prime is 21221121210187. The next prime is 21221121210221. The reversal of 21221121210220 is 2201212112212.

It is not an unprimeable number, because it can be changed into a prime (21221121210221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31943745 + ... + 32601304.

It is an arithmetic number, because the mean of its divisors is an integer number (984053832300).

Almost surely, 2^{21221121210220} is an apocalyptic number.

21221121210220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221121210220 is an abundant number, since it is smaller than the sum of its proper divisors (26013462740180).

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

21221121210220 is a wasteful number, since it uses less digits than its factorization.

21221121210220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64546042 (or 64546040 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21221121210220 its reverse (2201212112212), we get a palindrome (23422333322432).

The spelling of 21221121210220 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred ten thousand, two hundred twenty".