81398078 has 8 divisors (see below), whose sum is σ = 124695072. Its totient is φ = 39833056.

The previous prime is 81398077. The next prime is 81398087. The reversal of 81398078 is 87089318.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81398077) 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 3 ways as a sum of consecutive naturals, for example, 432875 + ... + 433062.

It is an arithmetic number, because the mean of its divisors is an integer number (15586884).

Almost surely, 2^81398078 is an apocalyptic number.

81398078 is a deficient number, since it is larger than the sum of its proper divisors (43296994).

81398078 is a wasteful number, since it uses less digits than its factorization.

81398078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 865986.

The product of its (nonzero) digits is 96768, while the sum is 44.

The square root of 81398078 is about 9022.0883391818. The cubic root of 81398078 is about 433.3825128930.

The spelling of 81398078 in words is "eighty-one million, three hundred ninety-eight thousand, seventy-eight".