6566621 has 2 divisors, whose sum is σ = 6566622. Its totient is φ = 6566620.

The previous prime is 6566617. The next prime is 6566629. The reversal of 6566621 is 1266656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5152900 + 1413721 = 2270^2 + 1189^2 .

It is a cyclic number.

It is not a de Polignac number, because 6566621 - 2² = 6566617 is a prime.

It is a super-2 number, since 2×6566621² = 86241022715282, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6566629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3283310 + 3283311.

It is an arithmetic number, because the mean of its divisors is an integer number (3283311).

Almost surely, 2^6566621 is an apocalyptic number.

It is an amenable number.

6566621 is a deficient number, since it is larger than the sum of its proper divisors (1).

6566621 is an equidigital number, since it uses as much as digits as its factorization.

6566621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 32.

The square root of 6566621 is about 2562.5419020964. The cubic root of 6566621 is about 187.2609908682.

The spelling of 6566621 in words is "six million, five hundred sixty-six thousand, six hundred twenty-one".