643452937 has 4 divisors (see below), whose sum is σ = 643868820. Its totient is φ = 643037056.

The previous prime is 643452919. The next prime is 643452947. The reversal of 643452937 is 739254346.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 251571321 + 391881616 = 15861^2 + 19796^2 .

It is a cyclic number.

It is not a de Polignac number, because 643452937 - 2⁷ = 643452809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643452893 and 643452902.

It is not an unprimeable number, because it can be changed into a prime (643452947) 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, 205612 + ... + 208717.

It is an arithmetic number, because the mean of its divisors is an integer number (160967205).

Almost surely, 2^643452937 is an apocalyptic number.

It is an amenable number.

643452937 is a deficient number, since it is larger than the sum of its proper divisors (415883).

643452937 is a wasteful number, since it uses less digits than its factorization.

643452937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415882.

The product of its digits is 544320, while the sum is 43.

The square root of 643452937 is about 25366.3741397938. The cubic root of 643452937 is about 863.3209153149.

The spelling of 643452937 in words is "six hundred forty-three million, four hundred fifty-two thousand, nine hundred thirty-seven".