21210121120212 has 18 divisors (see below), whose sum is σ = 53614472831738. Its totient is φ = 7070040373392.

The previous prime is 21210121120193. The next prime is 21210121120247. The reversal of 21210121120212 is 21202112101212.

21210121120212 is a `hidden beast` number, since 2 + 1 + 210 + 121 + 120 + 212 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21183981991236 + 26139128976 = 4602606^2 + 161676^2 .

It is a tau number, because it is divible by the number of its divisors (18).

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

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 294585015523 + ... + 294585015594.

Almost surely, 2^{21210121120212} is an apocalyptic number.

It is an amenable number.

21210121120212 is an abundant number, since it is smaller than the sum of its proper divisors (32404351711526).

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

21210121120212 is a wasteful number, since it uses less digits than its factorization.

21210121120212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 589170031127 (or 589170031122 counting only the distinct ones).

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

Adding to 21210121120212 its reverse (21202112101212), we get a palindrome (42412233221424).

The spelling of 21210121120212 in words is "twenty-one trillion, two hundred ten billion, one hundred twenty-one million, one hundred twenty thousand, two hundred twelve".