21193070081 has 2 divisors, whose sum is σ = 21193070082. Its totient is φ = 21193070080.

The previous prime is 21193070071. The next prime is 21193070083. The reversal of 21193070081 is 18007039112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20187863056 + 1005207025 = 142084^2 + 31705^2 .

It is a cyclic number.

It is not a de Polignac number, because 21193070081 - 2¹⁴ = 21193053697 is a prime.

It is a super-2 number, since 2×21193070081² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 21193070083, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21193070083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10596535040 + 10596535041.

It is an arithmetic number, because the mean of its divisors is an integer number (10596535041).

Almost surely, 2^21193070081 is an apocalyptic number.

It is an amenable number.

21193070081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21193070081 is an equidigital number, since it uses as much as digits as its factorization.

21193070081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 32.

The spelling of 21193070081 in words is "twenty-one billion, one hundred ninety-three million, seventy thousand, eighty-one".