21120112081 has 2 divisors, whose sum is σ = 21120112082. Its totient is φ = 21120112080.

The previous prime is 21120112037. The next prime is 21120112133. The reversal of 21120112081 is 18021102112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13820118481 + 7299993600 = 117559^2 + 85440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120112081 - 2²⁹ = 20583241169 is a prime.

It is a super-2 number, since 2×21120112081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21120112781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560056040 + 10560056041.

It is an arithmetic number, because the mean of its divisors is an integer number (10560056041).

Almost surely, 2^21120112081 is an apocalyptic number.

It is an amenable number.

21120112081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120112081 is an equidigital number, since it uses as much as digits as its factorization.

21120112081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21120112081 its reverse (18021102112), we get a palindrome (39141214193).

The spelling of 21120112081 in words is "twenty-one billion, one hundred twenty million, one hundred twelve thousand, eighty-one".