1604531 has 4 divisors (see below), whose sum is σ = 1689000. Its totient is φ = 1520064.

The previous prime is 1604521. The next prime is 1604539. The reversal of 1604531 is 1354061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1354061 = 181 ⋅7481.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1604531 is a prime.

It is a super-2 number, since 2×1604531² = 5149039459922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1604539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42206 + ... + 42243.

It is an arithmetic number, because the mean of its divisors is an integer number (422250).

2^1604531 is an apocalyptic number.

1604531 is a deficient number, since it is larger than the sum of its proper divisors (84469).

1604531 is an equidigital number, since it uses as much as digits as its factorization.

1604531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84468.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 1604531 is about 1266.7008328725. The cubic root of 1604531 is about 117.0710115099.

Adding to 1604531 its reverse (1354061), we get a palindrome (2958592).

The spelling of 1604531 in words is "one million, six hundred four thousand, five hundred thirty-one".