1645780 has 48 divisors (see below), whose sum is σ = 3749760. Its totient is φ = 604800.

The previous prime is 1645771. The next prime is 1645801. The reversal of 1645780 is 875461.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23145 + ... + 23215.

It is an arithmetic number, because the mean of its divisors is an integer number (78120).

2^1645780 is an apocalyptic number.

1645780 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 1645780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1874880).

1645780 is an abundant number, since it is smaller than the sum of its proper divisors (2103980).

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

1645780 is a wasteful number, since it uses less digits than its factorization.

1645780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 1645780 is about 1282.8795734596. The cubic root of 1645780 is about 118.0657490519.

It can be divided in two parts, 16 and 45780, that added together give a square (45796 = 214²).

The spelling of 1645780 in words is "one million, six hundred forty-five thousand, seven hundred eighty".