8666621 has 16 divisors (see below), whose sum is σ = 9480240. Its totient is φ = 7902720.

The previous prime is 8666597. The next prime is 8666627. The reversal of 8666621 is 1266668.

It can be written as a sum of positive squares in 8 ways, for example, as 657721 + 8008900 = 811^2 + 2830^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8666621 is a prime.

It is a super-2 number, since 2×8666621² = 150220639115282, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8666627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43895 + ... + 44091.

It is an arithmetic number, because the mean of its divisors is an integer number (592515).

Almost surely, 2^8666621 is an apocalyptic number.

It is an amenable number.

8666621 is a deficient number, since it is larger than the sum of its proper divisors (813619).

8666621 is a wasteful number, since it uses less digits than its factorization.

8666621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304.

The product of its digits is 20736, while the sum is 35.

The square root of 8666621 is about 2943.9125326680. The cubic root of 8666621 is about 205.4076441436.

The spelling of 8666621 in words is "eight million, six hundred sixty-six thousand, six hundred twenty-one".