81457181 has 8 divisors (see below), whose sum is σ = 90553344. Its totient is φ = 72765360.

The previous prime is 81457177. The next prime is 81457213. The reversal of 81457181 is 18175418.

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 81457181 - 2² = 81457177 is a prime.

It is a super-2 number, since 2×81457181² = 13270544672933522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81457141) 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, 100661 + ... + 101466.

It is an arithmetic number, because the mean of its divisors is an integer number (11319168).

Almost surely, 2^81457181 is an apocalyptic number.

It is an amenable number.

81457181 is a deficient number, since it is larger than the sum of its proper divisors (9096163).

81457181 is a wasteful number, since it uses less digits than its factorization.

81457181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202171.

The product of its digits is 8960, while the sum is 35.

The square root of 81457181 is about 9025.3632059879. The cubic root of 81457181 is about 433.4873802736.

The spelling of 81457181 in words is "eighty-one million, four hundred fifty-seven thousand, one hundred eighty-one".