643734375 has 56 divisors (see below), whose sum is σ = 1109985792. Its totient is φ = 331500000.

The previous prime is 643734353. The next prime is 643734391. The reversal of 643734375 is 573437346.

It is not a de Polignac number, because 643734375 - 2⁹ = 643733863 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1452904 + ... + 1453346.

Almost surely, 2^643734375 is an apocalyptic number.

643734375 is a deficient number, since it is larger than the sum of its proper divisors (466251417).

643734375 is an frugal number, since it uses more digits than its factorization.

643734375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507 (or 482 counting only the distinct ones).

The product of its digits is 635040, while the sum is 42.

The square root of 643734375 is about 25371.9209954627. The cubic root of 643734375 is about 863.4467654392.

The spelling of 643734375 in words is "six hundred forty-three million, seven hundred thirty-four thousand, three hundred seventy-five".