81080381 has 2 divisors, whose sum is σ = 81080382. Its totient is φ = 81080380.

The previous prime is 81080369. The next prime is 81080383. The reversal of 81080381 is 18308018.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69039481 + 12040900 = 8309^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 81080381 - 2¹⁸ = 80818237 is a prime.

It is a super-2 number, since 2×81080381² = 13148056366210322, which contains 22 as substring.

Together with 81080383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81080383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40540190 + 40540191.

It is an arithmetic number, because the mean of its divisors is an integer number (40540191).

Almost surely, 2^81080381 is an apocalyptic number.

It is an amenable number.

81080381 is a deficient number, since it is larger than the sum of its proper divisors (1).

81080381 is an equidigital number, since it uses as much as digits as its factorization.

81080381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 81080381 is about 9004.4645037892. The cubic root of 81080381 is about 432.8179465688.

Adding to 81080381 its reverse (18308018), we get a palindrome (99388399).

The spelling of 81080381 in words is "eighty-one million, eighty thousand, three hundred eighty-one".