1640545 has 4 divisors (see below), whose sum is σ = 1968660. Its totient is φ = 1312432.

The previous prime is 1640539. The next prime is 1640549. The reversal of 1640545 is 5450461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5450461 = 2293 ⋅2377.

It can be written as a sum of positive squares in 2 ways, for example, as 853776 + 786769 = 924^2 + 887^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640545 - 2⁹ = 1640033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1640549) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 164050 + ... + 164059.

It is an arithmetic number, because the mean of its divisors is an integer number (492165).

2^1640545 is an apocalyptic number.

It is an amenable number.

1640545 is a deficient number, since it is larger than the sum of its proper divisors (328115).

1640545 is an equidigital number, since it uses as much as digits as its factorization.

1640545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328114.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 1640545 is about 1280.8376165619. The cubic root of 1640545 is about 117.9404324455.

The spelling of 1640545 in words is "one million, six hundred forty thousand, five hundred forty-five".