1609221 has 4 divisors (see below), whose sum is σ = 2145632. Its totient is φ = 1072812.

The previous prime is 1609219. The next prime is 1609247. The reversal of 1609221 is 1229061.

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 not a de Polignac number, because 1609221 - 2¹ = 1609219 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1609211) 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, 268201 + ... + 268206.

It is an arithmetic number, because the mean of its divisors is an integer number (536408).

2^1609221 is an apocalyptic number.

It is an amenable number.

1609221 is a deficient number, since it is larger than the sum of its proper divisors (536411).

1609221 is an equidigital number, since it uses as much as digits as its factorization.

1609221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536410.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 1609221 is about 1268.5507479009. The cubic root of 1609221 is about 117.1849656696.

It can be divided in two parts, 1609 and 221, that added together give a triangular number (1830 = T₆₀).

The spelling of 1609221 in words is "one million, six hundred nine thousand, two hundred twenty-one".