81500518 has 24 divisors (see below), whose sum is σ = 134935416. Its totient is φ = 36891360.

The previous prime is 81500513. The next prime is 81500521.

81500518 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81500513) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73746 + ... + 74842.

It is an arithmetic number, because the mean of its divisors is an integer number (5622309).

Almost surely, 2^81500518 is an apocalyptic number.

81500518 is a deficient number, since it is larger than the sum of its proper divisors (53434898).

81500518 is a wasteful number, since it uses less digits than its factorization.

81500518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1428 (or 1417 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 28.

The square root of 81500518 is about 9027.7637319549. The cubic root of 81500518 is about 433.5642415637.

The spelling of 81500518 in words is "eighty-one million, five hundred thousand, five hundred eighteen".