99643509 has 18 divisors (see below), whose sum is σ = 167428950. Its totient is φ = 56938896.

The previous prime is 99643501. The next prime is 99643559. The reversal of 99643509 is 90534699.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 99500625 + 142884 = 9975^2 + 378^2 .

It is not a de Polignac number, because 99643509 - 2³ = 99643501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99643501) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 112534 + ... + 113415.

Almost surely, 2^99643509 is an apocalyptic number.

It is an amenable number.

99643509 is a deficient number, since it is larger than the sum of its proper divisors (67785441).

99643509 is a wasteful number, since it uses less digits than its factorization.

99643509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225969 (or 225959 counting only the distinct ones).

The product of its (nonzero) digits is 262440, while the sum is 45.

The square root of 99643509 is about 9982.1595358920. The cubic root of 99643509 is about 463.6066650894.

The spelling of 99643509 in words is "ninety-nine million, six hundred forty-three thousand, five hundred nine".