81389894 has 8 divisors (see below), whose sum is σ = 122331000. Its totient is φ = 40612896.

The previous prime is 81389873. The next prime is 81389953. The reversal of 81389894 is 49898318.

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

It is a Curzon number.

It is a congruent number.

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, 39779 + ... + 41774.

It is an arithmetic number, because the mean of its divisors is an integer number (15291375).

Almost surely, 2^81389894 is an apocalyptic number.

81389894 is a deficient number, since it is larger than the sum of its proper divisors (40941106).

81389894 is a wasteful number, since it uses less digits than its factorization.

81389894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82054.

The product of its digits is 497664, while the sum is 50.

The square root of 81389894 is about 9021.6347742524. The cubic root of 81389894 is about 433.3679878926.

The spelling of 81389894 in words is "eighty-one million, three hundred eighty-nine thousand, eight hundred ninety-four".