1645980 has 48 divisors (see below), whose sum is σ = 5268480. Its totient is φ = 376128.

The previous prime is 1645979. The next prime is 1645999. The reversal of 1645980 is 895461.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1540 + ... + 2379.

It is an arithmetic number, because the mean of its divisors is an integer number (109760).

2^1645980 is an apocalyptic number.

1645980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1645980 is an abundant number, since it is smaller than the sum of its proper divisors (3622500).

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

1645980 is a wasteful number, since it uses less digits than its factorization.

1645980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3938 (or 3936 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 1645980 is about 1282.9575207309. The cubic root of 1645980 is about 118.0705314232.

The spelling of 1645980 in words is "one million, six hundred forty-five thousand, nine hundred eighty".