6606655621 has 2 divisors, whose sum is σ = 6606655622. Its totient is φ = 6606655620.

The previous prime is 6606655589. The next prime is 6606655639. The reversal of 6606655621 is 1265566066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4437424996 + 2169230625 = 66614^2 + 46575^2 .

It is a cyclic number.

It is not a de Polignac number, because 6606655621 - 2⁵ = 6606655589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6606650621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3303327810 + 3303327811.

It is an arithmetic number, because the mean of its divisors is an integer number (3303327811).

Almost surely, 2^6606655621 is an apocalyptic number.

It is an amenable number.

6606655621 is a deficient number, since it is larger than the sum of its proper divisors (1).

6606655621 is an equidigital number, since it uses as much as digits as its factorization.

6606655621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 388800, while the sum is 43.

The square root of 6606655621 is about 81281.3362402464. The cubic root of 6606655621 is about 1876.4077720141.

The spelling of 6606655621 in words is "six billion, six hundred six million, six hundred fifty-five thousand, six hundred twenty-one".