21212102210220 has 72 divisors (see below), whose sum is σ = 66418969518720. Its totient is φ = 5474090891520.

The previous prime is 21212102210213. The next prime is 21212102210227. The reversal of 21212102210220 is 2201220121212.

It is a happy number.

21212102210220 is a `hidden beast` number, since 2 + 1 + 21 + 210 + 2 + 210 + 220 = 666.

It is an interprime number because it is at equal distance from previous prime (21212102210213) and next prime (21212102210227).

It is a super-3 number, since 3×21212102210220³ (a number of 41 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21212102210193 and 21212102210202.

It is not an unprimeable number, because it can be changed into a prime (21212102210227) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1900720425 + ... + 1900731584.

It is an arithmetic number, because the mean of its divisors is an integer number (922485687760).

Almost surely, 2^{21212102210220} is an apocalyptic number.

21212102210220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212102210220 is an abundant number, since it is smaller than the sum of its proper divisors (45206867308500).

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

21212102210220 is a wasteful number, since it uses less digits than its factorization.

21212102210220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3801452055 (or 3801452050 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21212102210220 its reverse (2201220121212), we get a palindrome (23413322331432).

The spelling of 21212102210220 in words is "twenty-one trillion, two hundred twelve billion, one hundred two million, two hundred ten thousand, two hundred twenty".