81293184 has 192 divisors, whose sum is σ = 283551840. Its totient is φ = 21823488.

The previous prime is 81293161. The next prime is 81293237. The reversal of 81293184 is 48139218.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136792 + ... + 137384.

Almost surely, 2^81293184 is an apocalyptic number.

81293184 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81293184, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141775920).

81293184 is an abundant number, since it is smaller than the sum of its proper divisors (202258656).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81293184 is a wasteful number, since it uses less digits than its factorization.

81293184 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637 (or 622 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 81293184 is about 9016.2732877836. The cubic root of 81293184 is about 433.1962727610.

The spelling of 81293184 in words is "eighty-one million, two hundred ninety-three thousand, one hundred eighty-four".