81383587 has 4 divisors (see below), whose sum is σ = 84008896. Its totient is φ = 78758280.

The previous prime is 81383581. The next prime is 81383611. The reversal of 81383587 is 78538318.

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 81383587 - 2³ = 81383579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81383581) 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, 1312608 + ... + 1312669.

It is an arithmetic number, because the mean of its divisors is an integer number (21002224).

Almost surely, 2^81383587 is an apocalyptic number.

81383587 is a deficient number, since it is larger than the sum of its proper divisors (2625309).

81383587 is a wasteful number, since it uses less digits than its factorization.

81383587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2625308.

The product of its digits is 161280, while the sum is 43.

The square root of 81383587 is about 9021.2852188588. The cubic root of 81383587 is about 433.3567935359.

The spelling of 81383587 in words is "eighty-one million, three hundred eighty-three thousand, five hundred eighty-seven".