81257578 has 8 divisors (see below), whose sum is σ = 122039460. Its totient is φ = 40577760.

The previous prime is 81257557. The next prime is 81257591. The reversal of 81257578 is 87575218.

It can be written as a sum of positive squares in 2 ways, for example, as 81234169 + 23409 = 9013^2 + 153^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23493 + ... + 26728.

Almost surely, 2^81257578 is an apocalyptic number.

81257578 is a deficient number, since it is larger than the sum of its proper divisors (40781882).

81257578 is a wasteful number, since it uses less digits than its factorization.

81257578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51032.

The product of its digits is 156800, while the sum is 43.

The square root of 81257578 is about 9014.2985306678. The cubic root of 81257578 is about 433.1330176056.

The spelling of 81257578 in words is "eighty-one million, two hundred fifty-seven thousand, five hundred seventy-eight".