643435361 has 4 divisors (see below), whose sum is σ = 677300400. Its totient is φ = 609570324.

The previous prime is 643435343. The next prime is 643435417. The reversal of 643435361 is 163534346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 163534346 = 2 ⋅81767173.

It is a cyclic number.

It is not a de Polignac number, because 643435361 - 2¹⁴ = 643418977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643435301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16932491 + ... + 16932528.

It is an arithmetic number, because the mean of its divisors is an integer number (169325100).

Almost surely, 2^643435361 is an apocalyptic number.

It is an amenable number.

643435361 is a deficient number, since it is larger than the sum of its proper divisors (33865039).

643435361 is a wasteful number, since it uses less digits than its factorization.

643435361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33865038.

The product of its digits is 77760, while the sum is 35.

The square root of 643435361 is about 25366.0276945366. The cubic root of 643435361 is about 863.3130546693.

The spelling of 643435361 in words is "six hundred forty-three million, four hundred thirty-five thousand, three hundred sixty-one".