1601656665 has 64 divisors (see below), whose sum is σ = 2980454400. Its totient is φ = 719357184.

The previous prime is 1601656621. The next prime is 1601656673. The reversal of 1601656665 is 5666561061.

It is not a de Polignac number, because 1601656665 - 2⁸ = 1601656409 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2430106 + ... + 2430764.

It is an arithmetic number, because the mean of its divisors is an integer number (46569600).

Almost surely, 2^1601656665 is an apocalyptic number.

1601656665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1601656665 is a deficient number, since it is larger than the sum of its proper divisors (1378797735).

1601656665 is a wasteful number, since it uses less digits than its factorization.

1601656665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1046.

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 1601656665 is about 40020.7029548458. The cubic root of 1601656665 is about 1170.0106325281.

The spelling of 1601656665 in words is "one billion, six hundred one million, six hundred fifty-six thousand, six hundred sixty-five".