81893438 has 16 divisors (see below), whose sum is σ = 134199936. Its totient is φ = 37170840.

The previous prime is 81893429. The next prime is 81893489. The reversal of 81893438 is 83439818.

It is a super-3 number, since 3×81893438³ (a number of 25 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 15845 + ... + 20367.

It is an arithmetic number, because the mean of its divisors is an integer number (8387496).

Almost surely, 2^81893438 is an apocalyptic number.

81893438 is a deficient number, since it is larger than the sum of its proper divisors (52306498).

81893438 is a wasteful number, since it uses less digits than its factorization.

81893438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5359.

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

The square root of 81893438 is about 9049.4993231670. The cubic root of 81893438 is about 434.2598732419.

The spelling of 81893438 in words is "eighty-one million, eight hundred ninety-three thousand, four hundred thirty-eight".