21331003081 has 2 divisors, whose sum is σ = 21331003082. Its totient is φ = 21331003080.

The previous prime is 21331003037. The next prime is 21331003123. The reversal of 21331003081 is 18030013312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20855981056 + 475022025 = 144416^2 + 21795^2 .

It is a cyclic number.

It is not a de Polignac number, because 21331003081 - 2²⁷ = 21196785353 is a prime.

It is a super-2 number, since 2×21331003081² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21331007081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665501540 + 10665501541.

It is an arithmetic number, because the mean of its divisors is an integer number (10665501541).

Almost surely, 2^21331003081 is an apocalyptic number.

It is an amenable number.

21331003081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331003081 is an equidigital number, since it uses as much as digits as its factorization.

21331003081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

Adding to 21331003081 its reverse (18030013312), we get a palindrome (39361016393).

The spelling of 21331003081 in words is "twenty-one billion, three hundred thirty-one million, three thousand, eighty-one".