643604208197 has 4 divisors (see below), whose sum is σ = 643669952256. Its totient is φ = 643538464140.

The previous prime is 643604208151. The next prime is 643604208209. The reversal of 643604208197 is 791802406346.

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 643604208197 - 2³² = 639309240901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643604208127) 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, 32857343 + ... + 32876924.

It is an arithmetic number, because the mean of its divisors is an integer number (160917488064).

Almost surely, 2^643604208197 is an apocalyptic number.

It is an amenable number.

643604208197 is a deficient number, since it is larger than the sum of its proper divisors (65744059).

643604208197 is an equidigital number, since it uses as much as digits as its factorization.

643604208197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65744058.

The product of its (nonzero) digits is 1741824, while the sum is 50.

The spelling of 643604208197 in words is "six hundred forty-three billion, six hundred four million, two hundred eight thousand, one hundred ninety-seven".