643729473 has 24 divisors (see below), whose sum is σ = 940542408. Its totient is φ = 424230912.

The previous prime is 643729469. The next prime is 643729483. The reversal of 643729473 is 374927346.

It can be written as a sum of positive squares in 4 ways, for example, as 58476609 + 585252864 = 7647^2 + 24192^2 .

It is not a de Polignac number, because 643729473 - 2² = 643729469 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643729423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 586261 + ... + 587357.

It is an arithmetic number, because the mean of its divisors is an integer number (39189267).

Almost surely, 2^643729473 is an apocalyptic number.

It is an amenable number.

643729473 is a deficient number, since it is larger than the sum of its proper divisors (296812935).

643729473 is a wasteful number, since it uses less digits than its factorization.

643729473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1793 (or 1790 counting only the distinct ones).

The product of its digits is 762048, while the sum is 45.

The square root of 643729473 is about 25371.8243924240. The cubic root of 643729473 is about 863.4445737346. Note that the first 3 decimals are identical.

The spelling of 643729473 in words is "six hundred forty-three million, seven hundred twenty-nine thousand, four hundred seventy-three".