3661649 has 2 divisors, whose sum is σ = 3661650. Its totient is φ = 3661648.

The previous prime is 3661643. The next prime is 3661673. The reversal of 3661649 is 9461663.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3489424 + 172225 = 1868^2 + 415^2 .

It is an emirp because it is prime and its reverse (9461663) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3661649 - 2⁴ = 3661633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (3661643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1830824 + 1830825.

It is an arithmetic number, because the mean of its divisors is an integer number (1830825).

Almost surely, 2^3661649 is an apocalyptic number.

It is an amenable number.

3661649 is a deficient number, since it is larger than the sum of its proper divisors (1).

3661649 is an equidigital number, since it uses as much as digits as its factorization.

3661649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 35.

The square root of 3661649 is about 1913.5435714924. The cubic root of 3661649 is about 154.1317953107.

The spelling of 3661649 in words is "three million, six hundred sixty-one thousand, six hundred forty-nine".