81578371 has 8 divisors (see below), whose sum is σ = 93347840. Its totient is φ = 69837768.

The previous prime is 81578327. The next prime is 81578383. The reversal of 81578371 is 17387518.

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 81578371 - 2⁷ = 81578243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81578311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 771 + ... + 12796.

It is an arithmetic number, because the mean of its divisors is an integer number (11668480).

Almost surely, 2^81578371 is an apocalyptic number.

81578371 is a deficient number, since it is larger than the sum of its proper divisors (11769469).

81578371 is a wasteful number, since it uses less digits than its factorization.

81578371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14433.

The product of its digits is 47040, while the sum is 40.

The square root of 81578371 is about 9032.0745678941. The cubic root of 81578371 is about 433.7022510535.

The spelling of 81578371 in words is "eighty-one million, five hundred seventy-eight thousand, three hundred seventy-one".