8691681 has 4 divisors (see below), whose sum is σ = 11588912. Its totient is φ = 5794452.

The previous prime is 8691673. The next prime is 8691689. The reversal of 8691681 is 1861968.

8691681 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

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 (8691673) and next prime (8691689).

It is not a de Polignac number, because 8691681 - 2³ = 8691673 is a prime.

It is a super-2 number, since 2×8691681² = 151090637211522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (8691689) 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, 1448611 + ... + 1448616.

It is an arithmetic number, because the mean of its divisors is an integer number (2897228).

Almost surely, 2^8691681 is an apocalyptic number.

It is an amenable number.

8691681 is a deficient number, since it is larger than the sum of its proper divisors (2897231).

8691681 is a wasteful number, since it uses less digits than its factorization.

8691681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2897230.

The product of its digits is 20736, while the sum is 39.

The square root of 8691681 is about 2948.1657009062. The cubic root of 8691681 is about 205.6054360350.

The spelling of 8691681 in words is "eight million, six hundred ninety-one thousand, six hundred eighty-one".