21010212111221 has 8 divisors (see below), whose sum is σ = 21110368078464. Its totient is φ = 20910289337280.

The previous prime is 21010212111209. The next prime is 21010212111223. The reversal of 21010212111221 is 12211121201012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21010212111221 - 2³⁰ = 21009138369397 is a prime.

It is a super-2 number, since 2×21010212111221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21010212111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212111223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58117700 + ... + 58478093.

It is an arithmetic number, because the mean of its divisors is an integer number (2638796009808).

Almost surely, 2^{21010212111221} is an apocalyptic number.

It is an amenable number.

21010212111221 is a deficient number, since it is larger than the sum of its proper divisors (100155967243).

21010212111221 is a wasteful number, since it uses less digits than its factorization.

21010212111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116596651.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21010212111221 its reverse (12211121201012), we get a palindrome (33221333312233).

The spelling of 21010212111221 in words is "twenty-one trillion, ten billion, two hundred twelve million, one hundred eleven thousand, two hundred twenty-one".