1649645 has 12 divisors (see below), whose sum is σ = 2042964. Its totient is φ = 1278720.

The previous prime is 1649639. The next prime is 1649647. The reversal of 1649645 is 5469461.

It can be written as a sum of positive squares in 6 ways, for example, as 401956 + 1247689 = 634^2 + 1117^2 .

It is not a de Polignac number, because 1649645 - 2¹⁸ = 1387501 is a prime.

It is a super-3 number, since 3×1649645³ = 13467678483837033375, which contains 333 as substring.

It is an Ulam number.

It is a Duffinian number.

Its product of digits (25920) is a multiple of the sum of its prime factors (320).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1649647) 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 11 ways as a sum of consecutive naturals, for example, 6725 + ... + 6965.

It is an arithmetic number, because the mean of its divisors is an integer number (170247).

2^1649645 is an apocalyptic number.

It is an amenable number.

1649645 is a deficient number, since it is larger than the sum of its proper divisors (393319).

1649645 is an equidigital number, since it uses as much as digits as its factorization.

1649645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 283 counting only the distinct ones).

The product of its digits is 25920, while the sum is 35.

The square root of 1649645 is about 1284.3850668705. The cubic root of 1649645 is about 118.1580998664.

The spelling of 1649645 in words is "one million, six hundred forty-nine thousand, six hundred forty-five".