81585078 has 8 divisors (see below), whose sum is σ = 163170168. Its totient is φ = 27195024.

The previous prime is 81585067. The next prime is 81585079. The reversal of 81585078 is 87058518.

It is a sphenic number, since it is the product of 3 distinct primes.

81585078 is an admirable number.

It is a super-2 number, since 2×81585078² = 13312249904532168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81585079) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6798751 + ... + 6798762.

It is an arithmetic number, because the mean of its divisors is an integer number (20396271).

Almost surely, 2^81585078 is an apocalyptic number.

81585078 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81585078 is a wasteful number, since it uses less digits than its factorization.

81585078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13597518.

The product of its (nonzero) digits is 89600, while the sum is 42.

The square root of 81585078 is about 9032.4458481632. The cubic root of 81585078 is about 433.7141363987.

The spelling of 81585078 in words is "eighty-one million, five hundred eighty-five thousand, seventy-eight".