81257147 has 8 divisors (see below), whose sum is σ = 81948672. Its totient is φ = 80569000.

The previous prime is 81257117. The next prime is 81257149. The reversal of 81257147 is 74175218.

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 81257147 - 2¹⁴ = 81240763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81257149) 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, 70022 + ... + 71172.

It is an arithmetic number, because the mean of its divisors is an integer number (10243584).

Almost surely, 2^81257147 is an apocalyptic number.

81257147 is a deficient number, since it is larger than the sum of its proper divisors (691525).

81257147 is a wasteful number, since it uses less digits than its factorization.

81257147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1689.

The product of its digits is 15680, while the sum is 35.

The square root of 81257147 is about 9014.2746241725. The cubic root of 81257147 is about 433.1322518076.

The spelling of 81257147 in words is "eighty-one million, two hundred fifty-seven thousand, one hundred forty-seven".