1603561 has 4 divisors (see below), whose sum is σ = 1630800. Its totient is φ = 1576324.

The previous prime is 1603541. The next prime is 1603573. The reversal of 1603561 is 1653061.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1603561 - 2⁵ = 1603529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1603501) 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 3 ways as a sum of consecutive naturals, for example, 13531 + ... + 13648.

It is an arithmetic number, because the mean of its divisors is an integer number (407700).

2^1603561 is an apocalyptic number.

It is an amenable number.

1603561 is a deficient number, since it is larger than the sum of its proper divisors (27239).

1603561 is an equidigital number, since it uses as much as digits as its factorization.

1603561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27238.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 1603561 is about 1266.3178905788. The cubic root of 1603561 is about 117.0474154617.

It can be divided in two parts, 160 and 3561, that added together give a square (3721 = 61²).

The spelling of 1603561 in words is "one million, six hundred three thousand, five hundred sixty-one".