1805642 has 4 divisors (see below), whose sum is σ = 2708466. Its totient is φ = 902820.

The previous prime is 1805641. The next prime is 1805651. The reversal of 1805642 is 2465081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1394761 + 410881 = 1181^2 + 641^2 .

It is not an unprimeable number, because it can be changed into a prime (1805641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 451409 + ... + 451412.

2^1805642 is an apocalyptic number.

1805642 is a deficient number, since it is larger than the sum of its proper divisors (902824).

1805642 is an equidigital number, since it uses as much as digits as its factorization.

1805642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 902823.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 1805642 is about 1343.7417906726. The cubic root of 1805642 is about 121.7710028460.

The spelling of 1805642 in words is "one million, eight hundred five thousand, six hundred forty-two".