1605144221 has 8 divisors (see below), whose sum is σ = 1646742720. Its totient is φ = 1564075872.

The previous prime is 1605144173. The next prime is 1605144227. The reversal of 1605144221 is 1224415061.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1605144221 - 2¹⁴ = 1605127837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605144227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126401 + ... + 138518.

It is an arithmetic number, because the mean of its divisors is an integer number (205842840).

Almost surely, 2^1605144221 is an apocalyptic number.

It is an amenable number.

1605144221 is a deficient number, since it is larger than the sum of its proper divisors (41598499).

1605144221 is an equidigital number, since it uses as much as digits as its factorization.

1605144221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265075.

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

The square root of 1605144221 is about 40064.2511598557. The cubic root of 1605144221 is about 1170.8592370939.

Adding to 1605144221 its reverse (1224415061), we get a palindrome (2829559282).

The spelling of 1605144221 in words is "one billion, six hundred five million, one hundred forty-four thousand, two hundred twenty-one".