1643921136 has 480 divisors, whose sum is σ = 5881766400. Its totient is φ = 434903040.

The previous prime is 1643921129. The next prime is 1643921183. The reversal of 1643921136 is 6311293461.

1643921136 is a `hidden beast` number, since 1 + 6 + 439 + 211 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1643921136.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 18470980 + ... + 18471068.

It is an arithmetic number, because the mean of its divisors is an integer number (12253680).

Almost surely, 2^1643921136 is an apocalyptic number.

1643921136 is a gapful number since it is divisible by the number (16) 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 1643921136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2940883200).

1643921136 is an abundant number, since it is smaller than the sum of its proper divisors (4237845264).

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

1643921136 is a wasteful number, since it uses less digits than its factorization.

1643921136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 141 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 1643921136 is about 40545.2973352028. The cubic root of 1643921136 is about 1180.2128161594.

The spelling of 1643921136 in words is "one billion, six hundred forty-three million, nine hundred twenty-one thousand, one hundred thirty-six".