1645840 has 40 divisors (see below), whose sum is σ = 4374720. Its totient is φ = 564096.

The previous prime is 1645829. The next prime is 1645843. The reversal of 1645840 is 485461.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 1645799 and 1645808.

It is not an unprimeable number, because it can be changed into a prime (1645843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 910 + ... + 2029.

It is an arithmetic number, because the mean of its divisors is an integer number (109368).

2^1645840 is an apocalyptic number.

1645840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645840 is an abundant number, since it is smaller than the sum of its proper divisors (2728880).

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

1645840 is a wasteful number, since it uses less digits than its factorization.

1645840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2959 (or 2953 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 1645840 is about 1282.9029581383. The cubic root of 1645840 is about 118.0671838040.

It can be divided in two parts, 1645 and 840, that added together give a triangular number (2485 = T₇₀).

The spelling of 1645840 in words is "one million, six hundred forty-five thousand, eight hundred forty".