20101211212221 has 6 divisors (see below), whose sum is σ = 29035082862110. Its totient is φ = 13400807474808.

The previous prime is 20101211212189. The next prime is 20101211212237. The reversal of 20101211212221 is 12221211210102.

20101211212221 is a `hidden beast` number, since 20 + 1 + 0 + 1 + 211 + 212 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 15740151672996 + 4361059539225 = 3967386^2 + 2088315^2 .

It is not a de Polignac number, because 20101211212221 - 2⁵ = 20101211212189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101211212194 and 20101211212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101211202221) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1116733956226 + ... + 1116733956243.

Almost surely, 2^{20101211212221} is an apocalyptic number.

It is an amenable number.

20101211212221 is a deficient number, since it is larger than the sum of its proper divisors (8933871649889).

20101211212221 is a wasteful number, since it uses less digits than its factorization.

20101211212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2233467912475 (or 2233467912472 counting only the distinct ones).

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

Adding to 20101211212221 its reverse (12221211210102), we get a palindrome (32322422422323).

The spelling of 20101211212221 in words is "twenty trillion, one hundred one billion, two hundred eleven million, two hundred twelve thousand, two hundred twenty-one".