21201221212110 has 48 divisors (see below), whose sum is σ = 55123420491360. Its totient is φ = 5653633826880.

The previous prime is 21201221212103. The next prime is 21201221212117. The reversal of 21201221212110 is 1121212210212.

21201221212110 is a `hidden beast` number, since 2 + 120 + 1 + 221 + 212 + 110 = 666.

It is an interprime number because it is at equal distance from previous prime (21201221212103) and next prime (21201221212117).

It is a super-2 number, since 2×21201221212110² (a number of 27 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201221212117) 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, 28989540 + ... + 29711880.

It is an arithmetic number, because the mean of its divisors is an integer number (1148404593570).

Almost surely, 2^{21201221212110} is an apocalyptic number.

21201221212110 is an abundant number, since it is smaller than the sum of its proper divisors (33922199279250).

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

21201221212110 is a wasteful number, since it uses less digits than its factorization.

21201221212110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1048473 (or 1048470 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21201221212110 its reverse (1121212210212), we get a palindrome (22322433422322).

The spelling of 21201221212110 in words is "twenty-one trillion, two hundred one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred ten".