81315080 has 128 divisors (see below), whose sum is σ = 241678080. Its totient is φ = 23838720.

The previous prime is 81315071. The next prime is 81315083. The reversal of 81315080 is 8051318.

It is a super-2 number, since 2×81315080² = 13224284470812800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81315083) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51584 + ... + 53136.

It is an arithmetic number, because the mean of its divisors is an integer number (1888110).

Almost surely, 2^81315080 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81315080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120839040).

81315080 is an abundant number, since it is smaller than the sum of its proper divisors (160363000).

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

81315080 is a wasteful number, since it uses less digits than its factorization.

81315080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1599 (or 1595 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 81315080 is about 9017.4874549400. The cubic root of 81315080 is about 433.2351625081.

Adding to 81315080 its reverse (8051318), we get a palindrome (89366398).

The spelling of 81315080 in words is "eighty-one million, three hundred fifteen thousand, eighty".