81504181 has 8 divisors (see below), whose sum is σ = 91980000. Its totient is φ = 71539440.

The previous prime is 81504169. The next prime is 81504191. The reversal of 81504181 is 18140518.

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

It is a cyclic number.

It is not a de Polignac number, because 81504181 - 2⁵ = 81504149 is a prime.

It is a super-2 number, since 2×81504181² = 13285863040961522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81504131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 127431 + ... + 128068.

It is an arithmetic number, because the mean of its divisors is an integer number (11497500).

Almost surely, 2^81504181 is an apocalyptic number.

It is an amenable number.

81504181 is a deficient number, since it is larger than the sum of its proper divisors (10475819).

81504181 is a wasteful number, since it uses less digits than its factorization.

81504181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255539.

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 81504181 is about 9027.9666038372. The cubic root of 81504181 is about 433.5707369091.

Adding to 81504181 its reverse (18140518), we get a palindrome (99644699).

The spelling of 81504181 in words is "eighty-one million, five hundred four thousand, one hundred eighty-one".