21210121210110 has 128 divisors (see below), whose sum is σ = 61603711902720. Its totient is φ = 4562461292544.

The previous prime is 21210121210097. The next prime is 21210121210129. The reversal of 21210121210110 is 1101212101212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21210121210110.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42725301 + ... + 43218879.

It is an arithmetic number, because the mean of its divisors is an integer number (481278999240).

Almost surely, 2^{21210121210110} is an apocalyptic number.

21210121210110 is an abundant number, since it is smaller than the sum of its proper divisors (40393590692610).

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

21210121210110 is a wasteful number, since it uses less digits than its factorization.

21210121210110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505650.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21210121210110 its reverse (1101212101212), we get a palindrome (22311333311322).

The spelling of 21210121210110 in words is "twenty-one trillion, two hundred ten billion, one hundred twenty-one million, two hundred ten thousand, one hundred ten".