1604521 has 2 divisors, whose sum is σ = 1604522. Its totient is φ = 1604520.

The previous prime is 1604513. The next prime is 1604539. The reversal of 1604521 is 1254061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1590121 + 14400 = 1261^2 + 120^2 .

It is an emirp because it is prime and its reverse (1254061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1604521 - 2³ = 1604513 is a prime.

It is a Chen prime.

1604521 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1604501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802260 + 802261.

It is an arithmetic number, because the mean of its divisors is an integer number (802261).

2^1604521 is an apocalyptic number.

It is an amenable number.

1604521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1604521 is an equidigital number, since it uses as much as digits as its factorization.

1604521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1604521 is about 1266.6968856044. The cubic root of 1604521 is about 117.0707683002.

Adding to 1604521 its reverse (1254061), we get a palindrome (2858582).

The spelling of 1604521 in words is "one million, six hundred four thousand, five hundred twenty-one".