1605204225 has 27 divisors (see below), whose sum is σ = 2876175939. Its totient is φ = 855788400.

The previous prime is 1605204187. The next prime is 1605204241. The reversal of 1605204225 is 5224025061.

The square root of 1605204225 is 40065.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 577873521 + 1027330704 = 24039^2 + 32052^2 .

It is not a de Polignac number, because 1605204225 - 2¹⁷ = 1605073153 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 599640 + ... + 602310.

Almost surely, 2^1605204225 is an apocalyptic number.

1605204225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1605204225 is the 40065-th square number.

1605204225 is the 20033-rd centered octagonal number.

It is an amenable number.

1605204225 is a deficient number, since it is larger than the sum of its proper divisors (1270971714).

1605204225 is an frugal number, since it uses more digits than its factorization.

1605204225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5358 (or 2679 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The cubic root of 1605204225 is about 1170.8738267200.

Adding to 1605204225 its reverse (5224025061), we get a palindrome (6829229286).

The spelling of 1605204225 in words is "one billion, six hundred five million, two hundred four thousand, two hundred twenty-five".