1643275980 has 72 divisors (see below), whose sum is σ = 4999844304. Its totient is φ = 436867200.

The previous prime is 1643275967. The next prime is 1643275999. The reversal of 1643275980 is 895723461.

1643275980 is a `hidden beast` number, since 16 + 43 + 2 + 7 + 598 + 0 = 666.

1643275980 is digitally balanced in base 4 and base 10, because in such bases it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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

1643275980 is strictly pandigital in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 45790 + ... + 73370.

It is an arithmetic number, because the mean of its divisors is an integer number (69442282).

It is a 1-persistent number, because it is pandigital, but 2⋅1643275980 = 3286551960 is not.

Almost surely, 2^1643275980 is an apocalyptic number.

1643275980 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 1643275980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2499922152).

1643275980 is an abundant number, since it is smaller than the sum of its proper divisors (3356568324).

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

1643275980 is a wasteful number, since it uses less digits than its factorization.

1643275980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27927 (or 27922 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 1643275980 is about 40537.3405639788. The cubic root of 1643275980 is about 1180.0584046549.

The spelling of 1643275980 in words is "one billion, six hundred forty-three million, two hundred seventy-five thousand, nine hundred eighty".