81138017 has 4 divisors (see below), whose sum is σ = 81156096. Its totient is φ = 81119940.

The previous prime is 81138011. The next prime is 81138023. The reversal of 81138017 is 71083118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (81138011) and next prime (81138023).

It is a cyclic number.

It is not a de Polignac number, because 81138017 - 2⁸ = 81137761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81138011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3392 + ... + 13182.

It is an arithmetic number, because the mean of its divisors is an integer number (20289024).

Almost surely, 2^81138017 is an apocalyptic number.

It is an amenable number.

81138017 is a deficient number, since it is larger than the sum of its proper divisors (18079).

81138017 is an equidigital number, since it uses as much as digits as its factorization.

81138017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18078.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 81138017 is about 9007.6643476542. The cubic root of 81138017 is about 432.9204785100.

The spelling of 81138017 in words is "eighty-one million, one hundred thirty-eight thousand, seventeen".