643849574 has 4 divisors (see below), whose sum is σ = 965774364. Its totient is φ = 321924786.

The previous prime is 643849553. The next prime is 643849607. The reversal of 643849574 is 475948346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 475948346 = 2 ⋅237974173.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160962392 + ... + 160962395.

It is an arithmetic number, because the mean of its divisors is an integer number (241443591).

Almost surely, 2^643849574 is an apocalyptic number.

643849574 is a deficient number, since it is larger than the sum of its proper divisors (321924790).

643849574 is a wasteful number, since it uses less digits than its factorization.

643849574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321924789.

The product of its digits is 2903040, while the sum is 50.

The square root of 643849574 is about 25374.1911004075. The cubic root of 643849574 is about 863.4982681888.

The spelling of 643849574 in words is "six hundred forty-three million, eight hundred forty-nine thousand, five hundred seventy-four".