21221201212101 has 40 divisors (see below), whose sum is σ = 36616974666624. Its totient is φ = 12104784996480.

The previous prime is 21221201212061. The next prime is 21221201212109. The reversal of 21221201212101 is 10121210212212.

21221201212101 is a `hidden beast` number, since 21 + 221 + 201 + 212 + 10 + 1 = 666.

It is not a de Polignac number, because 21221201212101 - 2³⁰ = 21220127470277 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221201212109) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 700493245 + ... + 700523538.

Almost surely, 2^{21221201212101} is an apocalyptic number.

It is an amenable number.

21221201212101 is a deficient number, since it is larger than the sum of its proper divisors (15395773454523).

21221201212101 is a wasteful number, since it uses less digits than its factorization.

21221201212101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1401016823 (or 1401016814 counting only the distinct ones).

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

Adding to 21221201212101 its reverse (10121210212212), we get a palindrome (31342411424313).

The spelling of 21221201212101 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred one million, two hundred twelve thousand, one hundred one".