6655645561 has 2 divisors, whose sum is σ = 6655645562. Its totient is φ = 6655645560.

The previous prime is 6655645559. The next prime is 6655645589. The reversal of 6655645561 is 1655465566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5944410000 + 711235561 = 77100^2 + 26669^2 .

It is a cyclic number.

It is not a de Polignac number, because 6655645561 - 2¹ = 6655645559 is a prime.

Together with 6655645559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (6655645541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3327822780 + 3327822781.

It is an arithmetic number, because the mean of its divisors is an integer number (3327822781).

Almost surely, 2^6655645561 is an apocalyptic number.

It is an amenable number.

6655645561 is a deficient number, since it is larger than the sum of its proper divisors (1).

6655645561 is an equidigital number, since it uses as much as digits as its factorization.

6655645561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240000, while the sum is 49.

The square root of 6655645561 is about 81582.1399633523. The cubic root of 6655645561 is about 1881.0343599719.

The spelling of 6655645561 in words is "six billion, six hundred fifty-five million, six hundred forty-five thousand, five hundred sixty-one".