643499999999 has 8 divisors (see below), whose sum is σ = 654450631440. Its totient is φ = 632550830400.

The previous prime is 643499999957. The next prime is 643500000053. The reversal of 643499999999 is 999999994346.

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 643499999999 - 2¹⁶ = 643499934463 is a prime.

It is a Duffinian number.

643499999999 is a modest number, since divided by 999999 gives 643499 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643499999939) 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, 541409 + ... + 1257029.

It is an arithmetic number, because the mean of its divisors is an integer number (81806328930).

Almost surely, 2^643499999999 is an apocalyptic number.

643499999999 is a deficient number, since it is larger than the sum of its proper divisors (10950631441).

643499999999 is a wasteful number, since it uses less digits than its factorization.

643499999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730921.

The product of its digits is 12397455648, while the sum is 89.

The spelling of 643499999999 in words is "six hundred forty-three billion, four hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".