8661641 has 2 divisors, whose sum is σ = 8661642. Its totient is φ = 8661640.

The previous prime is 8661629. The next prime is 8661643. The reversal of 8661641 is 1461668.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6760000 + 1901641 = 2600^2 + 1379^2 .

It is a cyclic number.

It is not a de Polignac number, because 8661641 - 2⁶ = 8661577 is a prime.

It is a Sophie Germain prime.

Together with 8661643, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 8661598 and 8661607.

It is not a weakly prime, because it can be changed into another prime (8661643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4330820 + 4330821.

It is an arithmetic number, because the mean of its divisors is an integer number (4330821).

Almost surely, 2^8661641 is an apocalyptic number.

It is an amenable number.

8661641 is a deficient number, since it is larger than the sum of its proper divisors (1).

8661641 is an equidigital number, since it uses as much as digits as its factorization.

8661641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 32.

The square root of 8661641 is about 2943.0665979553. The cubic root of 8661641 is about 205.3682929339.

The spelling of 8661641 in words is "eight million, six hundred sixty-one thousand, six hundred forty-one".