1643156680 has 64 divisors (see below), whose sum is σ = 4142249280. Its totient is φ = 581356800.

The previous prime is 1643156663. The next prime is 1643156729. The reversal of 1643156680 is 866513461.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34186 + ... + 66745.

It is an arithmetic number, because the mean of its divisors is an integer number (64722645).

Almost surely, 2^1643156680 is an apocalyptic number.

1643156680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643156680 is an abundant number, since it is smaller than the sum of its proper divisors (2499092600).

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

1643156680 is a wasteful number, since it uses less digits than its factorization.

1643156680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100990 (or 100986 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The square root of 1643156680 is about 40535.8690544560. The cubic root of 1643156680 is about 1180.0298469899.

The spelling of 1643156680 in words is "one billion, six hundred forty-three million, one hundred fifty-six thousand, six hundred eighty".