81384398 has 4 divisors (see below), whose sum is σ = 122076600. Its totient is φ = 40692198.

The previous prime is 81384383. The next prime is 81384409. The reversal of 81384398 is 89348318.

It is a semiprime because it is the product of two 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 as a sum of consecutive naturals, namely, 20346098 + ... + 20346101.

It is an arithmetic number, because the mean of its divisors is an integer number (30519150).

Almost surely, 2^81384398 is an apocalyptic number.

81384398 is a deficient number, since it is larger than the sum of its proper divisors (40692202).

81384398 is a wasteful number, since it uses less digits than its factorization.

81384398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40692201.

The product of its digits is 165888, while the sum is 44.

The square root of 81384398 is about 9021.3301679963. The cubic root of 81384398 is about 433.3582330202.

The spelling of 81384398 in words is "eighty-one million, three hundred eighty-four thousand, three hundred ninety-eight".