81181424 has 10 divisors (see below), whose sum is σ = 157289040. Its totient is φ = 40590704.

The previous prime is 81181393. The next prime is 81181447. The reversal of 81181424 is 42418118.

It is a happy number.

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 as a sum of consecutive naturals, namely, 2536904 + ... + 2536935.

It is an arithmetic number, because the mean of its divisors is an integer number (15728904).

Almost surely, 2^81181424 is an apocalyptic number.

It is an amenable number.

81181424 is a deficient number, since it is larger than the sum of its proper divisors (76107616).

81181424 is a wasteful number, since it uses less digits than its factorization.

81181424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5073847 (or 5073841 counting only the distinct ones).

The product of its digits is 2048, while the sum is 29.

The square root of 81181424 is about 9010.0734736183. The cubic root of 81181424 is about 432.9976656282.

The spelling of 81181424 in words is "eighty-one million, one hundred eighty-one thousand, four hundred twenty-four".