81178486 has 4 divisors (see below), whose sum is σ = 121767732. Its totient is φ = 40589242.

The previous prime is 81178463. The next prime is 81178529. The reversal of 81178486 is 68487118.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20294620 + ... + 20294623.

It is an arithmetic number, because the mean of its divisors is an integer number (30441933).

Almost surely, 2^81178486 is an apocalyptic number.

81178486 is a deficient number, since it is larger than the sum of its proper divisors (40589246).

81178486 is a wasteful number, since it uses less digits than its factorization.

81178486 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40589245.

The product of its digits is 86016, while the sum is 43.

The square root of 81178486 is about 9009.9104324072. The cubic root of 81178486 is about 432.9924420914.

It can be divided in two parts, 811 and 78486, that added together give a palindrome (79297).

The spelling of 81178486 in words is "eighty-one million, one hundred seventy-eight thousand, four hundred eighty-six".