21002120121210 has 32 divisors (see below), whose sum is σ = 50410889939520. Its totient is φ = 5599920738048.

The previous prime is 21002120121167. The next prime is 21002120121377. The reversal of 21002120121210 is 1212102120012.

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 21002120121210.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40024212 + ... + 40545551.

It is an arithmetic number, because the mean of its divisors is an integer number (1575340310610).

Almost surely, 2^{21002120121210} is an apocalyptic number.

21002120121210 is an abundant number, since it is smaller than the sum of its proper divisors (29408769818310).

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

21002120121210 is a wasteful number, since it uses less digits than its factorization.

21002120121210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80578462.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21002120121210 its reverse (1212102120012), we get a palindrome (22214222241222).

The spelling of 21002120121210 in words is "twenty-one trillion, two billion, one hundred twenty million, one hundred twenty-one thousand, two hundred ten".