643644043 has 8 divisors (see below), whose sum is σ = 735763712. Its totient is φ = 551567016.

The previous prime is 643644007. The next prime is 643644049. The reversal of 643644043 is 340446346.

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

It is not a de Polignac number, because 643644043 - 2¹³ = 643635851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643644049) 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, 34396 + ... + 49702.

It is an arithmetic number, because the mean of its divisors is an integer number (91970464).

Almost surely, 2^643644043 is an apocalyptic number.

643644043 is a deficient number, since it is larger than the sum of its proper divisors (92119669).

643644043 is a wasteful number, since it uses less digits than its factorization.

643644043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21321.

The product of its (nonzero) digits is 82944, while the sum is 34.

The square root of 643644043 is about 25370.1407761171. The cubic root of 643644043 is about 863.4063758391.

The spelling of 643644043 in words is "six hundred forty-three million, six hundred forty-four thousand, forty-three".