21211112121210 has 128 divisors (see below), whose sum is σ = 61708078264320. Its totient is φ = 5141835720000.

The previous prime is 21211112121181. The next prime is 21211112121259. The reversal of 21211112121210 is 1212121111212.

It is a happy number.

21211112121210 is a `hidden beast` number, since 21 + 211 + 11 + 212 + 1 + 210 = 666.

It is a super-2 number, since 2×21211112121210² (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 an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 64436299 + ... + 64764641.

It is an arithmetic number, because the mean of its divisors is an integer number (482094361440).

Almost surely, 2^{21211112121210} is an apocalyptic number.

21211112121210 is an abundant number, since it is smaller than the sum of its proper divisors (40496966143110).

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

21211112121210 is a wasteful number, since it uses less digits than its factorization.

21211112121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350121 (or 350115 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21211112121210 its reverse (1212121111212), we get a palindrome (22423233232422).

It can be divided in two parts, 212111 and 12121210, that added together give a palindrome (12333321).

The spelling of 21211112121210 in words is "twenty-one trillion, two hundred eleven billion, one hundred twelve million, one hundred twenty-one thousand, two hundred ten".