81157518 has 48 divisors (see below), whose sum is σ = 195312240. Its totient is φ = 24968736.

The previous prime is 81157487. The next prime is 81157523. The reversal of 81157518 is 81575118.

It is a happy number.

81157518 is a `hidden beast` number, since 81 + 1 + 575 + 1 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4680 + ... + 13572.

It is an arithmetic number, because the mean of its divisors is an integer number (4069005).

Almost surely, 2^81157518 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81157518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97656120).

81157518 is an abundant number, since it is smaller than the sum of its proper divisors (114154722).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81157518 is a wasteful number, since it uses less digits than its factorization.

81157518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8930 (or 8911 counting only the distinct ones).

The product of its digits is 11200, while the sum is 36.

The square root of 81157518 is about 9008.7467496872. The cubic root of 81157518 is about 432.9551589483.

The spelling of 81157518 in words is "eighty-one million, one hundred fifty-seven thousand, five hundred eighteen".