6655561657 has 4 divisors (see below), whose sum is σ = 6672671460. Its totient is φ = 6638451856.

The previous prime is 6655561643. The next prime is 6655561663. The reversal of 6655561657 is 7561655566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4539929641 + 2115632016 = 67379^2 + 45996^2 .

It is a cyclic number.

It is not a de Polignac number, because 6655561657 - 2³¹ = 4508078009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6655561697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8554318 + ... + 8555095.

It is an arithmetic number, because the mean of its divisors is an integer number (1668167865).

Almost surely, 2^6655561657 is an apocalyptic number.

It is an amenable number.

6655561657 is a deficient number, since it is larger than the sum of its proper divisors (17109803).

6655561657 is a wasteful number, since it uses less digits than its factorization.

6655561657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17109802.

The product of its digits is 5670000, while the sum is 52.

The square root of 6655561657 is about 81581.6257315334. The cubic root of 6655561657 is about 1881.0264555561.

The spelling of 6655561657 in words is "six billion, six hundred fifty-five million, five hundred sixty-one thousand, six hundred fifty-seven".