81505087 has 8 divisors (see below), whose sum is σ = 82736640. Its totient is φ = 80279640.

The previous prime is 81505069. The next prime is 81505091. The reversal of 81505087 is 78050518.

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

It is a cyclic number.

It is not a de Polignac number, because 81505087 - 2¹⁵ = 81472319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81505037) 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, 30162 + ... + 32752.

It is an arithmetic number, because the mean of its divisors is an integer number (10342080).

Almost surely, 2^81505087 is an apocalyptic number.

81505087 is a deficient number, since it is larger than the sum of its proper divisors (1231553).

81505087 is a wasteful number, since it uses less digits than its factorization.

81505087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3053.

The product of its (nonzero) digits is 11200, while the sum is 34.

The square root of 81505087 is about 9028.0167811098. The cubic root of 81505087 is about 433.5723434264.

The spelling of 81505087 in words is "eighty-one million, five hundred five thousand, eighty-seven".