81575917 has 8 divisors (see below), whose sum is σ = 86394816. Its totient is φ = 76863072.

The previous prime is 81575891. The next prime is 81575939. The reversal of 81575917 is 71957518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81575917 - 2⁷ = 81575789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81575317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24928 + ... + 28009.

It is an arithmetic number, because the mean of its divisors is an integer number (10799352).

Almost surely, 2^81575917 is an apocalyptic number.

It is an amenable number.

81575917 is a deficient number, since it is larger than the sum of its proper divisors (4818899).

81575917 is a wasteful number, since it uses less digits than its factorization.

81575917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53027.

The product of its digits is 88200, while the sum is 43.

The square root of 81575917 is about 9031.9387176840. The cubic root of 81575917 is about 433.6979022048.

The spelling of 81575917 in words is "eighty-one million, five hundred seventy-five thousand, nine hundred seventeen".