1656605665 has 32 divisors (see below), whose sum is σ = 2338834176. Its totient is φ = 1110524160.

The previous prime is 1656605633. The next prime is 1656605669. The reversal of 1656605665 is 5665066561.

It is not a de Polignac number, because 1656605665 - 2⁵ = 1656605633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1656605669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 701667 + ... + 704023.

It is an arithmetic number, because the mean of its divisors is an integer number (73088568).

Almost surely, 2^1656605665 is an apocalyptic number.

It is an amenable number.

1656605665 is a deficient number, since it is larger than the sum of its proper divisors (682228511).

1656605665 is a wasteful number, since it uses less digits than its factorization.

1656605665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3369.

The product of its (nonzero) digits is 972000, while the sum is 46.

The square root of 1656605665 is about 40701.4209211423. The cubic root of 1656605665 is about 1183.2405574732.

The spelling of 1656605665 in words is "one billion, six hundred fifty-six million, six hundred five thousand, six hundred sixty-five".