643464999 has 16 divisors (see below), whose sum is σ = 962540800. Its totient is φ = 424810008.

The previous prime is 643464989. The next prime is 643465013. The reversal of 643464999 is 999464346.

It is not a de Polignac number, because 643464999 - 2¹¹ = 643462951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643464949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112909 + ... + 118470.

It is an arithmetic number, because the mean of its divisors is an integer number (60158800).

Almost surely, 2^643464999 is an apocalyptic number.

643464999 is a deficient number, since it is larger than the sum of its proper divisors (319075801).

643464999 is a wasteful number, since it uses less digits than its factorization.

643464999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231491 (or 231485 counting only the distinct ones).

The product of its digits is 5038848, while the sum is 54.

The square root of 643464999 is about 25366.6118943780. The cubic root of 643464999 is about 863.3263098104.

The spelling of 643464999 in words is "six hundred forty-three million, four hundred sixty-four thousand, nine hundred ninety-nine".