1643323812 has 24 divisors (see below), whose sum is σ = 4129378176. Its totient is φ = 505638048.

The previous prime is 1643323771. The next prime is 1643323817. The reversal of 1643323812 is 2183233461.

It is a super-2 number, since 2×1643323812² = 5401026302172422688, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1643323817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5266908 + ... + 5267219.

It is an arithmetic number, because the mean of its divisors is an integer number (172057424).

Almost surely, 2^1643323812 is an apocalyptic number.

1643323812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1643323812 is an abundant number, since it is smaller than the sum of its proper divisors (2486054364).

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

1643323812 is a wasteful number, since it uses less digits than its factorization.

1643323812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10534147 (or 10534145 counting only the distinct ones).

The product of its digits is 20736, while the sum is 33.

The square root of 1643323812 is about 40537.9305342540. The cubic root of 1643323812 is about 1180.0698541429.

The spelling of 1643323812 in words is "one billion, six hundred forty-three million, three hundred twenty-three thousand, eight hundred twelve".