643000073 has 4 divisors (see below), whose sum is σ = 643083588. Its totient is φ = 642916560.

The previous prime is 643000067. The next prime is 643000079. The reversal of 643000073 is 370000346.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (643000067) and next prime (643000079).

It can be written as a sum of positive squares in 2 ways, for example, as 74511424 + 568488649 = 8632^2 + 23843^2 .

It is a cyclic number.

It is not a de Polignac number, because 643000073 - 2¹⁸ = 642737929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643000079) 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, 28886 + ... + 46047.

It is an arithmetic number, because the mean of its divisors is an integer number (160770897).

Almost surely, 2^643000073 is an apocalyptic number.

It is an amenable number.

643000073 is a deficient number, since it is larger than the sum of its proper divisors (83515).

643000073 is an equidigital number, since it uses as much as digits as its factorization.

643000073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83514.

The product of its (nonzero) digits is 1512, while the sum is 23.

The square root of 643000073 is about 25357.4461056314. The cubic root of 643000073 is about 863.1183318792.

The spelling of 643000073 in words is "six hundred forty-three million, seventy-three", and thus it is an aban number.