8821661 has 2 divisors, whose sum is σ = 8821662. Its totient is φ = 8821660.

The previous prime is 8821633. The next prime is 8821663. The reversal of 8821661 is 1661288.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8323225 + 498436 = 2885^2 + 706^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8821661 is a prime.

Together with 8821663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8821663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4410830 + 4410831.

It is an arithmetic number, because the mean of its divisors is an integer number (4410831).

Almost surely, 2^8821661 is an apocalyptic number.

It is an amenable number.

8821661 is a deficient number, since it is larger than the sum of its proper divisors (1).

8821661 is an equidigital number, since it uses as much as digits as its factorization.

8821661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 32.

The square root of 8821661 is about 2970.1281117150. The cubic root of 8821661 is about 206.6252798961.

The spelling of 8821661 in words is "eight million, eight hundred twenty-one thousand, six hundred sixty-one".