20101221110161 has 2 divisors, whose sum is σ = 20101221110162. Its totient is φ = 20101221110160.

The previous prime is 20101221110101. The next prime is 20101221110207. The reversal of 20101221110161 is 16101112210102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17289961934400 + 2811259175761 = 4158120^2 + 1676681^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101221110161 - 2¹¹ = 20101221108113 is a prime.

It is a super-3 number, since 3×20101221110161³ (a number of 41 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20101221110101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050610555080 + 10050610555081.

It is an arithmetic number, because the mean of its divisors is an integer number (10050610555081).

Almost surely, 2^{20101221110161} is an apocalyptic number.

It is an amenable number.

20101221110161 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101221110161 is an equidigital number, since it uses as much as digits as its factorization.

20101221110161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 19.

Adding to 20101221110161 its reverse (16101112210102), we get a palindrome (36202333320263).

The spelling of 20101221110161 in words is "twenty trillion, one hundred one billion, two hundred twenty-one million, one hundred ten thousand, one hundred sixty-one".