3666521 has 2 divisors, whose sum is σ = 3666522. Its totient is φ = 3666520.

The previous prime is 3666493. The next prime is 3666529. The reversal of 3666521 is 1256663.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2676496 + 990025 = 1636^2 + 995^2 .

It is a cyclic number.

It is not a de Polignac number, because 3666521 - 2¹⁴ = 3650137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (3666529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1833260 + 1833261.

It is an arithmetic number, because the mean of its divisors is an integer number (1833261).

Almost surely, 2^3666521 is an apocalyptic number.

It is an amenable number.

3666521 is a deficient number, since it is larger than the sum of its proper divisors (1).

3666521 is an equidigital number, since it uses as much as digits as its factorization.

3666521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 29.

The square root of 3666521 is about 1914.8161791671. The cubic root of 3666521 is about 154.2001249352.

The spelling of 3666521 in words is "three million, six hundred sixty-six thousand, five hundred twenty-one".