21101211110081 has 2 divisors, whose sum is σ = 21101211110082. Its totient is φ = 21101211110080.

The previous prime is 21101211110071. The next prime is 21101211110117. The reversal of 21101211110081 is 18001111210112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12254655442225 + 8846555667856 = 3500665^2 + 2974316^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101211110081 is a prime.

It is a super-2 number, since 2×21101211110081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21101211110011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550605555040 + 10550605555041.

It is an arithmetic number, because the mean of its divisors is an integer number (10550605555041).

Almost surely, 2^{21101211110081} is an apocalyptic number.

It is an amenable number.

21101211110081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101211110081 is an equidigital number, since it uses as much as digits as its factorization.

21101211110081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 20.

Adding to 21101211110081 its reverse (18001111210112), we get a palindrome (39102322320193).

The spelling of 21101211110081 in words is "twenty-one trillion, one hundred one billion, two hundred eleven million, one hundred ten thousand, eighty-one".