81385894 has 4 divisors (see below), whose sum is σ = 122078844. Its totient is φ = 40692946.

The previous prime is 81385867. The next prime is 81385921. The reversal of 81385894 is 49858318.

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

It is an interprime number because it is at equal distance from previous prime (81385867) and next prime (81385921).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20346472 + ... + 20346475.

It is an arithmetic number, because the mean of its divisors is an integer number (30519711).

Almost surely, 2^81385894 is an apocalyptic number.

81385894 is a deficient number, since it is larger than the sum of its proper divisors (40692950).

81385894 is a wasteful number, since it uses less digits than its factorization.

81385894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40692949.

The product of its digits is 276480, while the sum is 46.

The square root of 81385894 is about 9021.4130822172. The cubic root of 81385894 is about 433.3608883201.

The spelling of 81385894 in words is "eighty-one million, three hundred eighty-five thousand, eight hundred ninety-four".