643165406 has 16 divisors (see below), whose sum is σ = 1046548944. Its totient is φ = 294677184.

The previous prime is 643165381. The next prime is 643165417. The reversal of 643165406 is 604561346.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86720 + ... + 93843.

It is an arithmetic number, because the mean of its divisors is an integer number (65409309).

Almost surely, 2^643165406 is an apocalyptic number.

643165406 is a deficient number, since it is larger than the sum of its proper divisors (403383538).

643165406 is a wasteful number, since it uses less digits than its factorization.

643165406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180715.

The product of its (nonzero) digits is 51840, while the sum is 35.

The square root of 643165406 is about 25360.7059444330. The cubic root of 643165406 is about 863.1923026920.

The spelling of 643165406 in words is "six hundred forty-three million, one hundred sixty-five thousand, four hundred six".