21110000081 has 2 divisors, whose sum is σ = 21110000082. Its totient is φ = 21110000080.

The previous prime is 21110000057. The next prime is 21110000101. The reversal of 21110000081 is 18000001112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18133315600 + 2976684481 = 134660^2 + 54559^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110000081 - 2³⁰ = 20036258257 is a prime.

It is a super-2 number, since 2×21110000081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21110000881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555000040 + 10555000041.

It is an arithmetic number, because the mean of its divisors is an integer number (10555000041).

Almost surely, 2^21110000081 is an apocalyptic number.

It is an amenable number.

21110000081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110000081 is an equidigital number, since it uses as much as digits as its factorization.

21110000081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21110000081 its reverse (18000001112), we get a palindrome (39110001193).

The spelling of 21110000081 in words is "twenty-one billion, one hundred ten million, eighty-one", and thus it is an aban number.