86891581 has 4 divisors (see below), whose sum is σ = 99304672. Its totient is φ = 74478492.

The previous prime is 86891561. The next prime is 86891599. The reversal of 86891581 is 18519868.

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 a cyclic number.

It is not a de Polignac number, because 86891581 - 2⁵ = 86891549 is a prime.

It is a super-2 number, since 2×86891581² = 15100293697359122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (86891561) 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, 6206535 + ... + 6206548.

It is an arithmetic number, because the mean of its divisors is an integer number (24826168).

Almost surely, 2^86891581 is an apocalyptic number.

It is an amenable number.

86891581 is a deficient number, since it is larger than the sum of its proper divisors (12413091).

86891581 is a wasteful number, since it uses less digits than its factorization.

86891581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12413090.

The product of its digits is 138240, while the sum is 46.

The square root of 86891581 is about 9321.5653728330. The cubic root of 86891581 is about 442.9206206169.

The spelling of 86891581 in words is "eighty-six million, eight hundred ninety-one thousand, five hundred eighty-one".