643444741 has 4 divisors (see below), whose sum is σ = 643541184. Its totient is φ = 643348300.

The previous prime is 643444727. The next prime is 643444783. The reversal of 643444741 is 147444346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643444741 - 2¹⁵ = 643411973 is a prime.

It is a super-2 number, since 2×643444741² = 828042269441114162, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 643444741.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643445741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37405 + ... + 51826.

It is an arithmetic number, because the mean of its divisors is an integer number (160885296).

Almost surely, 2^643444741 is an apocalyptic number.

It is an amenable number.

643444741 is a deficient number, since it is larger than the sum of its proper divisors (96443).

643444741 is an equidigital number, since it uses as much as digits as its factorization.

643444741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96442.

The product of its digits is 129024, while the sum is 37.

The square root of 643444741 is about 25366.2125868250. The cubic root of 643444741 is about 863.3172497745.

The spelling of 643444741 in words is "six hundred forty-three million, four hundred forty-four thousand, seven hundred forty-one".