81364687 has 4 divisors (see below), whose sum is σ = 81386800. Its totient is φ = 81342576.

The previous prime is 81364681. The next prime is 81364693. The reversal of 81364687 is 78646318.

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

It is an interprime number because it is at equal distance from previous prime (81364681) and next prime (81364693).

It is a cyclic number.

It is not a de Polignac number, because 81364687 - 2¹⁵ = 81331919 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 (81364681) 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, 4062 + ... + 13387.

It is an arithmetic number, because the mean of its divisors is an integer number (20346700).

Almost surely, 2^81364687 is an apocalyptic number.

81364687 is a deficient number, since it is larger than the sum of its proper divisors (22113).

81364687 is a wasteful number, since it uses less digits than its factorization.

81364687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22112.

The product of its digits is 193536, while the sum is 43.

The square root of 81364687 is about 9020.2376354506. The cubic root of 81364687 is about 433.3232442753.

The spelling of 81364687 in words is "eighty-one million, three hundred sixty-four thousand, six hundred eighty-seven".