8661643 has 2 divisors, whose sum is σ = 8661644. Its totient is φ = 8661642.

The previous prime is 8661641. The next prime is 8661673. The reversal of 8661643 is 3461668.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8661643 - 2¹ = 8661641 is a prime.

Together with 8661641, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 8661599 and 8661608.

It is not a weakly prime, because it can be changed into another prime (8661641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4330821 + 4330822.

It is an arithmetic number, because the mean of its divisors is an integer number (4330822).

Almost surely, 2^8661643 is an apocalyptic number.

8661643 is a deficient number, since it is larger than the sum of its proper divisors (1).

8661643 is an equidigital number, since it uses as much as digits as its factorization.

8661643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 34.

The square root of 8661643 is about 2943.0669377369. The cubic root of 8661643 is about 205.3683087406.

The spelling of 8661643 in words is "eight million, six hundred sixty-one thousand, six hundred forty-three".