8638661 has 2 divisors, whose sum is σ = 8638662. Its totient is φ = 8638660.

The previous prime is 8638633. The next prime is 8638687. The reversal of 8638661 is 1668368.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8014561 + 624100 = 2831^2 + 790^2 .

It is a cyclic number.

It is not a de Polignac number, because 8638661 - 2¹⁰ = 8637637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8638621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4319330 + 4319331.

It is an arithmetic number, because the mean of its divisors is an integer number (4319331).

Almost surely, 2^8638661 is an apocalyptic number.

It is an amenable number.

8638661 is a deficient number, since it is larger than the sum of its proper divisors (1).

8638661 is an equidigital number, since it uses as much as digits as its factorization.

8638661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 38.

The square root of 8638661 is about 2939.1599139890. The cubic root of 8638661 is about 205.1865127860.

The spelling of 8638661 in words is "eight million, six hundred thirty-eight thousand, six hundred sixty-one".