81041687 has 4 divisors (see below), whose sum is σ = 81063120. Its totient is φ = 81020256.

The previous prime is 81041671. The next prime is 81041711. The reversal of 81041687 is 78614018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81041687 - 2⁴ = 81041671 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 (81041617) 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 3 ways as a sum of consecutive naturals, for example, 3362 + ... + 13167.

It is an arithmetic number, because the mean of its divisors is an integer number (20265780).

Almost surely, 2^81041687 is an apocalyptic number.

81041687 is a deficient number, since it is larger than the sum of its proper divisors (21433).

81041687 is a wasteful number, since it uses less digits than its factorization.

81041687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21432.

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 81041687 is about 9002.3156465434. The cubic root of 81041687 is about 432.7490843596.

The spelling of 81041687 in words is "eighty-one million, forty-one thousand, six hundred eighty-seven".