81513860 has 12 divisors (see below), whose sum is σ = 171179148. Its totient is φ = 32605536.

The previous prime is 81513829. The next prime is 81513881. The reversal of 81513860 is 6831518.

It can be written as a sum of positive squares in 2 ways, for example, as 8479744 + 73034116 = 2912^2 + 8546^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2037827 + ... + 2037866.

It is an arithmetic number, because the mean of its divisors is an integer number (14264929).

Almost surely, 2^81513860 is an apocalyptic number.

It is an amenable number.

81513860 is an abundant number, since it is smaller than the sum of its proper divisors (89665288).

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

81513860 is a wasteful number, since it uses less digits than its factorization.

81513860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4075702 (or 4075700 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81513860 is about 9028.5026444034. The cubic root of 81513860 is about 433.5878990759.

The spelling of 81513860 in words is "eighty-one million, five hundred thirteen thousand, eight hundred sixty".