21323030081 has 2 divisors, whose sum is σ = 21323030082. Its totient is φ = 21323030080.

The previous prime is 21323030021. The next prime is 21323030089. The reversal of 21323030081 is 18003032312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17685010225 + 3638019856 = 132985^2 + 60316^2 .

It is a cyclic number.

It is not a de Polignac number, because 21323030081 - 2²⁶ = 21255921217 is a prime.

It is a super-2 number, since 2×21323030081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21323030089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661515040 + 10661515041.

It is an arithmetic number, because the mean of its divisors is an integer number (10661515041).

Almost surely, 2^21323030081 is an apocalyptic number.

It is an amenable number.

21323030081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323030081 is an equidigital number, since it uses as much as digits as its factorization.

21323030081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21323030081 its reverse (18003032312), we get a palindrome (39326062393).

The spelling of 21323030081 in words is "twenty-one billion, three hundred twenty-three million, thirty thousand, eighty-one".