643884955 has 8 divisors (see below), whose sum is σ = 883042272. Its totient is φ = 441521088.

The previous prime is 643884953. The next prime is 643884991. The reversal of 643884955 is 559488346.

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

It is a cyclic number.

It is not a de Polignac number, because 643884955 - 2¹ = 643884953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643884953) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9198322 + ... + 9198391.

It is an arithmetic number, because the mean of its divisors is an integer number (110380284).

Almost surely, 2^643884955 is an apocalyptic number.

643884955 is a deficient number, since it is larger than the sum of its proper divisors (239157317).

643884955 is a wasteful number, since it uses less digits than its factorization.

643884955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18396725.

The product of its digits is 4147200, while the sum is 52.

The square root of 643884955 is about 25374.8882756161. Note that the first 3 decimals coincide. The cubic root of 643884955 is about 863.5140849644.

The spelling of 643884955 in words is "six hundred forty-three million, eight hundred eighty-four thousand, nine hundred fifty-five".