643421605 has 8 divisors (see below), whose sum is σ = 812743200. Its totient is φ = 487645776.

The previous prime is 643421591. The next prime is 643421633. The reversal of 643421605 is 506124346.

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

It is a cyclic number.

It is not a de Polignac number, because 643421605 - 2¹³ = 643413413 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3386335 + ... + 3386524.

It is an arithmetic number, because the mean of its divisors is an integer number (101592900).

Almost surely, 2^643421605 is an apocalyptic number.

It is an amenable number.

643421605 is a deficient number, since it is larger than the sum of its proper divisors (169321595).

643421605 is a wasteful number, since it uses less digits than its factorization.

643421605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6772883.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 643421605 is about 25365.7565430247. The cubic root of 643421605 is about 863.3069023709.

The spelling of 643421605 in words is "six hundred forty-three million, four hundred twenty-one thousand, six hundred five".