21210212122220 has 96 divisors (see below), whose sum is σ = 49142814642432. Its totient is φ = 7625383200000.

The previous prime is 21210212122159. The next prime is 21210212122277. The reversal of 21210212122220 is 2222121201212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21210212122192 and 21210212122201.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14663315 + ... + 16044725.

It is an arithmetic number, because the mean of its divisors is an integer number (511904319192).

Almost surely, 2^{21210212122220} is an apocalyptic number.

21210212122220 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 21210212122220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24571407321216).

21210212122220 is an abundant number, since it is smaller than the sum of its proper divisors (27932602520212).

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

21210212122220 is a wasteful number, since it uses less digits than its factorization.

21210212122220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1382223 (or 1382221 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21210212122220 its reverse (2222121201212), we get a palindrome (23432333323432).

The spelling of 21210212122220 in words is "twenty-one trillion, two hundred ten billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty".