643017653 has 16 divisors (see below), whose sum is σ = 666783216. Its totient is φ = 619799040.

The previous prime is 643017631. The next prime is 643017659. The reversal of 643017653 is 356710346.

It can be written as a sum of positive squares in 8 ways, for example, as 84971524 + 558046129 = 9218^2 + 23623^2 .

It is not a de Polignac number, because 643017653 - 2¹⁶ = 642952117 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 (643017659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 876875 + ... + 877607.

It is an arithmetic number, because the mean of its divisors is an integer number (41673951).

Almost surely, 2^643017653 is an apocalyptic number.

It is an amenable number.

643017653 is a deficient number, since it is larger than the sum of its proper divisors (23765563).

643017653 is a wasteful number, since it uses less digits than its factorization.

643017653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1064.

The product of its (nonzero) digits is 45360, while the sum is 35.

The square root of 643017653 is about 25357.7927470038. The cubic root of 643017653 is about 863.1261978617.

Adding to 643017653 its reverse (356710346), we get a palindrome (999727999).

The spelling of 643017653 in words is "six hundred forty-three million, seventeen thousand, six hundred fifty-three".