81511118 has 8 divisors (see below), whose sum is σ = 131671848. Its totient is φ = 37620504.

The previous prime is 81511117. The next prime is 81511127. The reversal of 81511118 is 81111518.

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

It is a Harshad number since it is a multiple of its sum of digits (26), and also a Moran number because the ratio is a prime number: 3135043 = 81511118 / (8 + 1 + 5 + 1 + 1 + 1 + 1 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81511117) 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, 1567496 + ... + 1567547.

It is an arithmetic number, because the mean of its divisors is an integer number (16458981).

Almost surely, 2^81511118 is an apocalyptic number.

81511118 is a deficient number, since it is larger than the sum of its proper divisors (50160730).

81511118 is a wasteful number, since it uses less digits than its factorization.

81511118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3135058.

The product of its digits is 320, while the sum is 26.

The square root of 81511118 is about 9028.3507907037. The cubic root of 81511118 is about 433.5830372796.

The spelling of 81511118 in words is "eighty-one million, five hundred eleven thousand, one hundred eighteen".