81161518 has 8 divisors (see below), whose sum is σ = 122373648. Its totient is φ = 40370304.

The previous prime is 81161513. The next prime is 81161543. The reversal of 81161518 is 81516118.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81161518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81161513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104746 + ... + 105517.

It is an arithmetic number, because the mean of its divisors is an integer number (15296706).

Almost surely, 2^81161518 is an apocalyptic number.

81161518 is a deficient number, since it is larger than the sum of its proper divisors (41212130).

81161518 is a wasteful number, since it uses less digits than its factorization.

81161518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210458.

The product of its digits is 1920, while the sum is 31.

The square root of 81161518 is about 9008.9687534146. The cubic root of 81161518 is about 432.9622718329.

The spelling of 81161518 in words is "eighty-one million, one hundred sixty-one thousand, five hundred eighteen".