1645404 has 12 divisors (see below), whose sum is σ = 3839304. Its totient is φ = 548464.

The previous prime is 1645367. The next prime is 1645409. The reversal of 1645404 is 4045461.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645409) 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 3 ways as a sum of consecutive naturals, for example, 68547 + ... + 68570.

It is an arithmetic number, because the mean of its divisors is an integer number (319942).

2^1645404 is an apocalyptic number.

It is an amenable number.

1645404 is an abundant number, since it is smaller than the sum of its proper divisors (2193900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1645404 is a wasteful number, since it uses less digits than its factorization.

1645404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137124 (or 137122 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 1645404 is about 1282.7330197668. The cubic root of 1645404 is about 118.0567571448.

The spelling of 1645404 in words is "one million, six hundred forty-five thousand, four hundred four".