20010111221 has 2 divisors, whose sum is σ = 20010111222. Its totient is φ = 20010111220.

The previous prime is 20010111203. The next prime is 20010111227. The reversal of 20010111221 is 12211101002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11912631025 + 8097480196 = 109145^2 + 89986^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20010111221 is a prime.

It is a super-2 number, since 2×20010111221² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20010111227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005055610 + 10005055611.

It is an arithmetic number, because the mean of its divisors is an integer number (10005055611).

Almost surely, 2^20010111221 is an apocalyptic number.

It is an amenable number.

20010111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20010111221 is an equidigital number, since it uses as much as digits as its factorization.

20010111221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 20010111221 its reverse (12211101002), we get a palindrome (32221212223).

The spelling of 20010111221 in words is "twenty billion, ten million, one hundred eleven thousand, two hundred twenty-one".