21121021101210 has 128 divisors (see below), whose sum is σ = 53219630776320. Its totient is φ = 5354315155200.

The previous prime is 21121021101161. The next prime is 21121021101251. The reversal of 21121021101210 is 1210112012112.

It is a happy number.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121021101210.

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, 146082855 + ... + 146227365.

It is an arithmetic number, because the mean of its divisors is an integer number (415778365440).

Almost surely, 2^{21121021101210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121021101210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26609815388160).

21121021101210 is an abundant number, since it is smaller than the sum of its proper divisors (32098609675110).

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

21121021101210 is a wasteful number, since it uses less digits than its factorization.

21121021101210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145844.

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

Adding to 21121021101210 its reverse (1210112012112), we get a palindrome (22331133113322).

The spelling of 21121021101210 in words is "twenty-one trillion, one hundred twenty-one billion, twenty-one million, one hundred one thousand, two hundred ten".