6621649 has 2 divisors, whose sum is σ = 6621650. Its totient is φ = 6621648.

The previous prime is 6621607. The next prime is 6621691. The reversal of 6621649 is 9461266.

It is a balanced prime because it is at equal distance from previous prime (6621607) and next prime (6621691).

It can be written as a sum of positive squares in only one way, i.e., 5198400 + 1423249 = 2280^2 + 1193^2 .

It is a cyclic number.

It is not a de Polignac number, because 6621649 - 2⁹ = 6621137 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6621749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3310824 + 3310825.

It is an arithmetic number, because the mean of its divisors is an integer number (3310825).

Almost surely, 2^6621649 is an apocalyptic number.

It is an amenable number.

6621649 is a deficient number, since it is larger than the sum of its proper divisors (1).

6621649 is an equidigital number, since it uses as much as digits as its factorization.

6621649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 34.

The square root of 6621649 is about 2573.2564971258. The cubic root of 6621649 is about 187.7826161729.

The spelling of 6621649 in words is "six million, six hundred twenty-one thousand, six hundred forty-nine".