81575385 has 8 divisors (see below), whose sum is σ = 130520640. Its totient is φ = 43506864.

The previous prime is 81575371. The next prime is 81575387. The reversal of 81575385 is 58357518.

It is a happy number.

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

It is not a de Polignac number, because 81575385 - 2⁴ = 81575369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81575387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2719165 + ... + 2719194.

It is an arithmetic number, because the mean of its divisors is an integer number (16315080).

Almost surely, 2^81575385 is an apocalyptic number.

It is an amenable number.

81575385 is a deficient number, since it is larger than the sum of its proper divisors (48945255).

81575385 is a wasteful number, since it uses less digits than its factorization.

81575385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5438367.

The product of its digits is 168000, while the sum is 42.

The square root of 81575385 is about 9031.9092665947. The cubic root of 81575385 is about 433.6969594111.

The spelling of 81575385 in words is "eighty-one million, five hundred seventy-five thousand, three hundred eighty-five".