81136384 has 72 divisors (see below), whose sum is σ = 194915840. Its totient is φ = 32928768.

The previous prime is 81136381. The next prime is 81136409. The reversal of 81136384 is 48363118.

It is a super-2 number, since 2×81136384² = 13166225617190912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81136381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32857 + ... + 35239.

Almost surely, 2^81136384 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81136384, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97457920).

81136384 is an abundant number, since it is smaller than the sum of its proper divisors (113779456).

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

81136384 is a wasteful number, since it uses less digits than its factorization.

81136384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2425 (or 2411 counting only the distinct ones).

The product of its digits is 13824, while the sum is 34.

The square root of 81136384 is about 9007.5737021686. The cubic root of 81136384 is about 432.9175741424.

The spelling of 81136384 in words is "eighty-one million, one hundred thirty-six thousand, three hundred eighty-four".