643347671 has 4 divisors (see below), whose sum is σ = 643404744. Its totient is φ = 643290600.

The previous prime is 643347637. The next prime is 643347673. The reversal of 643347671 is 176743346.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 643347671 - 2²² = 639153367 is a prime.

It is a super-2 number, since 2×643347671² = 827792451562248482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643347673) 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, 5345 + ... + 36266.

It is an arithmetic number, because the mean of its divisors is an integer number (160851186).

Almost surely, 2^643347671 is an apocalyptic number.

643347671 is a deficient number, since it is larger than the sum of its proper divisors (57073).

643347671 is a wasteful number, since it uses less digits than its factorization.

643347671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57072.

The product of its digits is 254016, while the sum is 41.

The square root of 643347671 is about 25364.2991426927. The cubic root of 643347671 is about 863.2738342774.

The spelling of 643347671 in words is "six hundred forty-three million, three hundred forty-seven thousand, six hundred seventy-one".