81518530 has 32 divisors (see below), whose sum is σ = 154068480. Its totient is φ = 31013760.

The previous prime is 81518527. The next prime is 81518557. The reversal of 81518530 is 3581518.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 81518492 and 81518501.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16062 + ... + 20518.

It is an arithmetic number, because the mean of its divisors is an integer number (4814640).

Almost surely, 2^81518530 is an apocalyptic number.

81518530 is a deficient number, since it is larger than the sum of its proper divisors (72549950).

81518530 is a wasteful number, since it uses less digits than its factorization.

81518530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4554.

The product of its (nonzero) digits is 4800, while the sum is 31.

The square root of 81518530 is about 9028.7612660874. The cubic root of 81518530 is about 433.5961791272.

The spelling of 81518530 in words is "eighty-one million, five hundred eighteen thousand, five hundred thirty".