643045505 has 4 divisors (see below), whose sum is σ = 771654612. Its totient is φ = 514436400.

The previous prime is 643045483. The next prime is 643045537. The reversal of 643045505 is 505540346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 505540346 = 2 ⋅252770173.

It can be written as a sum of positive squares in 2 ways, for example, as 266375041 + 376670464 = 16321^2 + 19408^2 .

It is a de Polignac number, because none of the positive numbers 2^k-643045505 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64304546 + ... + 64304555.

It is an arithmetic number, because the mean of its divisors is an integer number (192913653).

Almost surely, 2^643045505 is an apocalyptic number.

It is an amenable number.

643045505 is a deficient number, since it is larger than the sum of its proper divisors (128609107).

643045505 is a wasteful number, since it uses less digits than its factorization.

643045505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128609106.

The product of its (nonzero) digits is 36000, while the sum is 32.

The square root of 643045505 is about 25358.3419213481. The cubic root of 643045505 is about 863.1386596470.

The spelling of 643045505 in words is "six hundred forty-three million, forty-five thousand, five hundred five".