81487117 has 4 divisors (see below), whose sum is σ = 81896800. Its totient is φ = 81077436.

The previous prime is 81487093. The next prime is 81487141. The reversal of 81487117 is 71178418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (81487093) and next prime (81487141).

It is a cyclic number.

It is not a de Polignac number, because 81487117 - 2⁷ = 81486989 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 (81487177) 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, 204543 + ... + 204940.

It is an arithmetic number, because the mean of its divisors is an integer number (20474200).

Almost surely, 2^81487117 is an apocalyptic number.

It is an amenable number.

81487117 is a deficient number, since it is larger than the sum of its proper divisors (409683).

81487117 is a wasteful number, since it uses less digits than its factorization.

81487117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409682.

The product of its digits is 12544, while the sum is 37.

The square root of 81487117 is about 9027.0214910567. The cubic root of 81487117 is about 433.5404768359.

The spelling of 81487117 in words is "eighty-one million, four hundred eighty-seven thousand, one hundred seventeen".