81360513 has 12 divisors (see below), whose sum is σ = 126560980. Its totient is φ = 50067936.

The previous prime is 81360511. The next prime is 81360551. The reversal of 81360513 is 31506318.

It can be written as a sum of positive squares in 2 ways, for example, as 30338064 + 51022449 = 5508^2 + 7143^2 .

It is not a de Polignac number, because 81360513 - 2¹ = 81360511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81360511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 347578 + ... + 347811.

Almost surely, 2^81360513 is an apocalyptic number.

It is an amenable number.

81360513 is a deficient number, since it is larger than the sum of its proper divisors (45200467).

81360513 is a wasteful number, since it uses less digits than its factorization.

81360513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 695408 (or 695405 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 81360513 is about 9020.0062638559. The cubic root of 81360513 is about 433.3158343361.

The spelling of 81360513 in words is "eighty-one million, three hundred sixty thousand, five hundred thirteen".