8381661 has 4 divisors (see below), whose sum is σ = 11175552. Its totient is φ = 5587772.

The previous prime is 8381627. The next prime is 8381669. The reversal of 8381661 is 1661838.

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 8381661 - 2⁷ = 8381533 is a prime.

It is a super-2 number, since 2×8381661² = 140504482237842, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8381669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1396941 + ... + 1396946.

It is an arithmetic number, because the mean of its divisors is an integer number (2793888).

Almost surely, 2^8381661 is an apocalyptic number.

It is an amenable number.

8381661 is a deficient number, since it is larger than the sum of its proper divisors (2793891).

8381661 is a wasteful number, since it uses less digits than its factorization.

8381661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2793890.

The product of its digits is 6912, while the sum is 33.

The square root of 8381661 is about 2895.1098424758. The cubic root of 8381661 is about 203.1312295052.

The spelling of 8381661 in words is "eight million, three hundred eighty-one thousand, six hundred sixty-one".