21760331081 has 2 divisors, whose sum is σ = 21760331082. Its totient is φ = 21760331080.

The previous prime is 21760331069. The next prime is 21760331083. The reversal of 21760331081 is 18013306712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11668320400 + 10092010681 = 108020^2 + 100459^2 .

It is a cyclic number.

It is not a de Polignac number, because 21760331081 - 2¹⁸ = 21760068937 is a prime.

It is a super-2 number, since 2×21760331081² (a number of 21 digits) contains 22 as substring.

Together with 21760331083, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21760331083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10880165540 + 10880165541.

It is an arithmetic number, because the mean of its divisors is an integer number (10880165541).

Almost surely, 2^21760331081 is an apocalyptic number.

It is an amenable number.

21760331081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21760331081 is an equidigital number, since it uses as much as digits as its factorization.

21760331081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

Adding to 21760331081 its reverse (18013306712), we get a palindrome (39773637793).

The spelling of 21760331081 in words is "twenty-one billion, seven hundred sixty million, three hundred thirty-one thousand, eighty-one".