643372705 has 8 divisors (see below), whose sum is σ = 772216704. Its totient is φ = 514585200.

The previous prime is 643372679. The next prime is 643372747. The reversal of 643372705 is 507273346.

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

It is not a de Polignac number, because 643372705 - 2¹⁹ = 642848417 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17290 + ... + 39820.

It is an arithmetic number, because the mean of its divisors is an integer number (96527088).

Almost surely, 2^643372705 is an apocalyptic number.

It is an amenable number.

643372705 is a deficient number, since it is larger than the sum of its proper divisors (128843999).

643372705 is a wasteful number, since it uses less digits than its factorization.

643372705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28247.

The product of its (nonzero) digits is 105840, while the sum is 37.

The square root of 643372705 is about 25364.7926267888. The cubic root of 643372705 is about 863.2850313941.

The spelling of 643372705 in words is "six hundred forty-three million, three hundred seventy-two thousand, seven hundred five".