643437497 has 4 divisors (see below), whose sum is σ = 651189840. Its totient is φ = 635685156.

The previous prime is 643437467. The next prime is 643437521. The reversal of 643437497 is 794734346.

643437497 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 643437497 - 2⁶ = 643437433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643437427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3876047 + ... + 3876212.

It is an arithmetic number, because the mean of its divisors is an integer number (162797460).

Almost surely, 2^643437497 is an apocalyptic number.

It is an amenable number.

643437497 is a deficient number, since it is larger than the sum of its proper divisors (7752343).

643437497 is an equidigital number, since it uses as much as digits as its factorization.

643437497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7752342.

The product of its digits is 1524096, while the sum is 47.

The square root of 643437497 is about 25366.0697980590. The cubic root of 643437497 is about 863.3140099761.

The spelling of 643437497 in words is "six hundred forty-three million, four hundred thirty-seven thousand, four hundred ninety-seven".