1645563 has 4 divisors (see below), whose sum is σ = 2194088. Its totient is φ = 1097040.

The previous prime is 1645561. The next prime is 1645601. The reversal of 1645563 is 3655461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3655461 = 3 ⋅1218487.

It is not a de Polignac number, because 1645563 - 2¹ = 1645561 is a prime.

It is a D-number.

It is a Duffinian number.

1645563 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1645563.

It is not an unprimeable number, because it can be changed into a prime (1645561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274258 + ... + 274263.

It is an arithmetic number, because the mean of its divisors is an integer number (548522).

2^1645563 is an apocalyptic number.

1645563 is a deficient number, since it is larger than the sum of its proper divisors (548525).

1645563 is an equidigital number, since it uses as much as digits as its factorization.

1645563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548524.

The product of its digits is 10800, while the sum is 30.

The square root of 1645563 is about 1282.7949953130. The cubic root of 1645563 is about 118.0605597407.

The spelling of 1645563 in words is "one million, six hundred forty-five thousand, five hundred sixty-three".