1643230640 has 80 divisors (see below), whose sum is σ = 3956056320. Its totient is φ = 634106880.

The previous prime is 1643230619. The next prime is 1643230651. The reversal of 1643230640 is 460323461.

It is a tau number, because it is divible by the number of its divisors (80).

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, 983726 + ... + 985394.

It is an arithmetic number, because the mean of its divisors is an integer number (49450704).

Almost surely, 2^1643230640 is an apocalyptic number.

1643230640 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 1643230640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1978028160).

1643230640 is an abundant number, since it is smaller than the sum of its proper divisors (2312825680).

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

1643230640 is a wasteful number, since it uses less digits than its factorization.

1643230640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110 (or 2104 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 1643230640 is about 40536.7813226457. The cubic root of 1643230640 is about 1180.0475514688.

The spelling of 1643230640 in words is "one billion, six hundred forty-three million, two hundred thirty thousand, six hundred forty".