1659645 has 24 divisors (see below), whose sum is σ = 3099096. Its totient is φ = 816768.

The previous prime is 1659643. The next prime is 1659649. The reversal of 1659645 is 5469561.

1659645 is a `hidden beast` number, since 1 + 6 + 5 + 9 + 645 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 49284 + 1610361 = 222^2 + 1269^2 .

It is not a de Polignac number, because 1659645 - 2¹ = 1659643 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1659643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 834 + ... + 2003.

It is an arithmetic number, because the mean of its divisors is an integer number (129129).

2^1659645 is an apocalyptic number.

1659645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1659645 is a deficient number, since it is larger than the sum of its proper divisors (1439451).

1659645 is a wasteful number, since it uses less digits than its factorization.

1659645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2861 (or 2858 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 1659645 is about 1288.2720985879. The cubic root of 1659645 is about 118.3963736487.

It can be divided in two parts, 16596 and 45, that added together give a square (16641 = 129²).

The spelling of 1659645 in words is "one million, six hundred fifty-nine thousand, six hundred forty-five".