1645920 has 120 divisors (see below), whose sum is σ = 5854464. Its totient is φ = 435456.

The previous prime is 1645909. The next prime is 1645927. The reversal of 1645920 is 295461.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645927) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12897 + ... + 13023.

2^1645920 is an apocalyptic number.

1645920 is a gapful number since it is divisible by the number (10) 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 1645920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2927232).

1645920 is an abundant number, since it is smaller than the sum of its proper divisors (4208544).

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

1645920 is a wasteful number, since it uses less digits than its factorization.

1645920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 1645920 is about 1282.9341370468. The cubic root of 1645920 is about 118.0690967525.

It can be divided in two parts, 164 and 5920, that added together give a square (6084 = 78²).

The spelling of 1645920 in words is "one million, six hundred forty-five thousand, nine hundred twenty".