81817080 has 32 divisors (see below), whose sum is σ = 245451600. Its totient is φ = 21817856.

The previous prime is 81817069. The next prime is 81817081. The reversal of 81817080 is 8071818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81817081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 340785 + ... + 341024.

Almost surely, 2^81817080 is an apocalyptic number.

It is an amenable number.

81817080 is an abundant number, since it is smaller than the sum of its proper divisors (163634520).

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

81817080 is a wasteful number, since it uses less digits than its factorization.

81817080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681823 (or 681819 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 33.

The square root of 81817080 is about 9045.2794318363. The cubic root of 81817080 is about 434.1248623159.

Adding to 81817080 its reverse (8071818), we get a palindrome (89888898).

The spelling of 81817080 in words is "eighty-one million, eight hundred seventeen thousand, eighty".