1620404 has 24 divisors (see below), whose sum is σ = 2994600. Its totient is φ = 766080.

The previous prime is 1620403. The next prime is 1620413. The reversal of 1620404 is 4040261.

It can be written as a sum of positive squares in 4 ways, for example, as 204304 + 1416100 = 452^2 + 1190^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6962 + ... + 7190.

It is an arithmetic number, because the mean of its divisors is an integer number (124775).

2^1620404 is an apocalyptic number.

It is an amenable number.

1620404 is a deficient number, since it is larger than the sum of its proper divisors (1374196).

1620404 is a wasteful number, since it uses less digits than its factorization.

1620404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 321 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1620404 is about 1272.9509024310. The cubic root of 1620404 is about 117.4557914269.

Adding to 1620404 its reverse (4040261), we get a palindrome (5660665).

The spelling of 1620404 in words is "one million, six hundred twenty thousand, four hundred four".