643441326 has 16 divisors (see below), whose sum is σ = 1403872128. Its totient is φ = 194982200.

The previous prime is 643441303. The next prime is 643441339. The reversal of 643441326 is 623144346.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4874490 + ... + 4874621.

It is an arithmetic number, because the mean of its divisors is an integer number (87742008).

Almost surely, 2^643441326 is an apocalyptic number.

643441326 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

643441326 is an abundant number, since it is smaller than the sum of its proper divisors (760430802).

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

643441326 is a wasteful number, since it uses less digits than its factorization.

643441326 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9749127.

The product of its digits is 41472, while the sum is 33.

The square root of 643441326 is about 25366.1452727844. The cubic root of 643441326 is about 863.3157224568.

The spelling of 643441326 in words is "six hundred forty-three million, four hundred forty-one thousand, three hundred twenty-six".