1643445804 has 384 divisors, whose sum is σ = 5462360064. Its totient is φ = 370944000.

The previous prime is 1643445803. The next prime is 1643445809. The reversal of 1643445804 is 4085443461.

It is a super-2 number, since 2×1643445804² = 5401828221370412832, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (1643445803) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 23147089 + ... + 23147159.

It is an arithmetic number, because the mean of its divisors is an integer number (14224896).

Almost surely, 2^1643445804 is an apocalyptic number.

1643445804 is a gapful number since it is divisible by the number (14) 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 1643445804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2731180032).

1643445804 is an abundant number, since it is smaller than the sum of its proper divisors (3818914260).

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

1643445804 is a wasteful number, since it uses less digits than its factorization.

1643445804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 39.

The square root of 1643445804 is about 40539.4351712009. The cubic root of 1643445804 is about 1180.0990542147.

The spelling of 1643445804 in words is "one billion, six hundred forty-three million, four hundred forty-five thousand, eight hundred four".