1604021 has 2 divisors, whose sum is σ = 1604022. Its totient is φ = 1604020.

The previous prime is 1604017. The next prime is 1604051. The reversal of 1604021 is 1204061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 819025 + 784996 = 905^2 + 886^2 .

It is a cyclic number.

It is not a de Polignac number, because 1604021 - 2² = 1604017 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1603987 and 1604005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1604051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802010 + 802011.

It is an arithmetic number, because the mean of its divisors is an integer number (802011).

2^1604021 is an apocalyptic number.

It is an amenable number.

1604021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1604021 is an equidigital number, since it uses as much as digits as its factorization.

1604021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 1604021 is about 1266.4995065139. The cubic root of 1604021 is about 117.0586065262.

Adding to 1604021 its reverse (1204061), we get a palindrome (2808082).

It can be divided in two parts, 16040 and 21, that added together give a palindrome (16061).

The spelling of 1604021 in words is "one million, six hundred four thousand, twenty-one".