643722443 has 8 divisors (see below), whose sum is σ = 792273888. Its totient is φ = 509318784.

The previous prime is 643722439. The next prime is 643722461. The reversal of 643722443 is 344227346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643722443 - 2² = 643722439 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643722433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3536846 + ... + 3537027.

It is an arithmetic number, because the mean of its divisors is an integer number (99034236).

Almost surely, 2^643722443 is an apocalyptic number.

643722443 is a deficient number, since it is larger than the sum of its proper divisors (148551445).

643722443 is a wasteful number, since it uses less digits than its factorization.

643722443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7073893.

The product of its digits is 96768, while the sum is 35.

The square root of 643722443 is about 25371.6858525404. The cubic root of 643722443 is about 863.4414305729.

Adding to 643722443 its reverse (344227346), we get a palindrome (987949789).

The spelling of 643722443 in words is "six hundred forty-three million, seven hundred twenty-two thousand, four hundred forty-three".