643956266 has 8 divisors (see below), whose sum is σ = 966288864. Its totient is φ = 321859980.

The previous prime is 643956263. The next prime is 643956293. The reversal of 643956266 is 662659346.

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

It is a self number, because there is not a number n which added to its sum of digits gives 643956266.

It is not an unprimeable number, because it can be changed into a prime (643956263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52100 + ... + 63263.

It is an arithmetic number, because the mean of its divisors is an integer number (120786108).

Almost surely, 2^643956266 is an apocalyptic number.

643956266 is a deficient number, since it is larger than the sum of its proper divisors (322332598).

643956266 is a wasteful number, since it uses less digits than its factorization.

643956266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118156.

The product of its digits is 1399680, while the sum is 47.

The square root of 643956266 is about 25376.2933857567. The cubic root of 643956266 is about 863.5459621806.

The spelling of 643956266 in words is "six hundred forty-three million, nine hundred fifty-six thousand, two hundred sixty-six".