1645644 has 96 divisors (see below), whose sum is σ = 5193216. Its totient is φ = 391680.

The previous prime is 1645643. The next prime is 1645661. The reversal of 1645644 is 4465461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11944 + ... + 12080.

It is an arithmetic number, because the mean of its divisors is an integer number (54096).

2^1645644 is an apocalyptic number.

1645644 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1645644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2596608).

1645644 is an abundant number, since it is smaller than the sum of its proper divisors (3547572).

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

1645644 is a wasteful number, since it uses less digits than its factorization.

1645644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 173 counting only the distinct ones).

The product of its digits is 11520, while the sum is 30.

The square root of 1645644 is about 1282.8265666098. The cubic root of 1645644 is about 118.0624968181.

The spelling of 1645644 in words is "one million, six hundred forty-five thousand, six hundred forty-four".