81580016 has 40 divisors (see below), whose sum is σ = 186877920. Its totient is φ = 33755904.

The previous prime is 81579989. The next prime is 81580019. The reversal of 81580016 is 61008518.

It is a Harshad number since it is a multiple of its sum of digits (29).

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9311 + ... + 15806.

It is an arithmetic number, because the mean of its divisors is an integer number (4671948).

Almost surely, 2^81580016 is an apocalyptic number.

It is an amenable number.

81580016 is an abundant number, since it is smaller than the sum of its proper divisors (105297904).

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

81580016 is a wasteful number, since it uses less digits than its factorization.

81580016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25161 (or 25155 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 29.

The square root of 81580016 is about 9032.1656317851. The cubic root of 81580016 is about 433.7051661866.

The spelling of 81580016 in words is "eighty-one million, five hundred eighty thousand, sixteen".