1645775280 has 160 divisors (see below), whose sum is σ = 5681779200. Its totient is φ = 437868288.

The previous prime is 1645775237. The next prime is 1645775293. The reversal of 1645775280 is 825775461.

1645775280 is a `hidden beast` number, since 16 + 45 + 77 + 528 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 31 ways as a sum of consecutive naturals, for example, 1854997 + ... + 1855883.

It is an arithmetic number, because the mean of its divisors is an integer number (35511120).

Almost surely, 2^1645775280 is an apocalyptic number.

1645775280 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 1645775280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2840889600).

1645775280 is an abundant number, since it is smaller than the sum of its proper divisors (4036003920).

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

1645775280 is a wasteful number, since it uses less digits than its factorization.

1645775280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768 (or 1756 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The square root of 1645775280 is about 40568.1559847129. The cubic root of 1645775280 is about 1180.6563618325.

The spelling of 1645775280 in words is "one billion, six hundred forty-five million, seven hundred seventy-five thousand, two hundred eighty".