81580015 has 48 divisors (see below), whose sum is σ = 116444160. Its totient is φ = 54648000.

The previous prime is 81579989. The next prime is 81580019. The reversal of 81580015 is 51008518.

It is not a de Polignac number, because 81580015 - 2⁵ = 81579983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81580019) 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 47 ways as a sum of consecutive naturals, for example, 540190 + ... + 540340.

It is an arithmetic number, because the mean of its divisors is an integer number (2425920).

Almost surely, 2^81580015 is an apocalyptic number.

81580015 is a deficient number, since it is larger than the sum of its proper divisors (34864145).

81580015 is a wasteful number, since it uses less digits than its factorization.

81580015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 233 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 28.

The square root of 81580015 is about 9032.1655764274. The cubic root of 81580015 is about 433.7051644144.

The spelling of 81580015 in words is "eighty-one million, five hundred eighty thousand, fifteen".