81715180 has 24 divisors (see below), whose sum is σ = 172917360. Its totient is φ = 32435520.

The previous prime is 81715169. The next prime is 81715189. The reversal of 81715180 is 8151718.

It is not an unprimeable number, because it can be changed into a prime (81715189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12975 + ... + 18214.

It is an arithmetic number, because the mean of its divisors is an integer number (7204890).

Almost surely, 2^81715180 is an apocalyptic number.

It is an amenable number.

81715180 is an abundant number, since it is smaller than the sum of its proper divisors (91202180).

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

81715180 is a wasteful number, since it uses less digits than its factorization.

81715180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31329 (or 31327 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 31.

The square root of 81715180 is about 9039.6449045303. The cubic root of 81715180 is about 433.9445588817.

Adding to 81715180 its reverse (8151718), we get a palindrome (89866898).

The spelling of 81715180 in words is "eighty-one million, seven hundred fifteen thousand, one hundred eighty".