1601665 has 16 divisors (see below), whose sum is σ = 2123856. Its totient is φ = 1152000.

The previous prime is 1601659. The next prime is 1601671. The reversal of 1601665 is 5661061.

It is an interprime number because it is at equal distance from previous prime (1601659) and next prime (1601671).

It can be written as a sum of positive squares in 8 ways, for example, as 199809 + 1401856 = 447^2 + 1184^2 .

It is not a de Polignac number, because 1601665 - 2¹¹ = 1599617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2365 + ... + 2965.

It is an arithmetic number, because the mean of its divisors is an integer number (132741).

2^1601665 is an apocalyptic number.

It is an amenable number.

1601665 is a deficient number, since it is larger than the sum of its proper divisors (522191).

1601665 is a wasteful number, since it uses less digits than its factorization.

1601665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1601665 is about 1265.5690419728. The cubic root of 1601665 is about 117.0012662098.

The spelling of 1601665 in words is "one million, six hundred one thousand, six hundred sixty-five".