643363651 has 4 divisors (see below), whose sum is σ = 735272752. Its totient is φ = 551454552.

The previous prime is 643363649. The next prime is 643363703. The reversal of 643363651 is 156363346.

643363651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 156363346 = 2 ⋅78181673.

It is a cyclic number.

It is not a de Polignac number, because 643363651 - 2¹ = 643363649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 643363651.

It is not an unprimeable number, because it can be changed into a prime (643363601) 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, 45954540 + ... + 45954553.

It is an arithmetic number, because the mean of its divisors is an integer number (183818188).

Almost surely, 2^643363651 is an apocalyptic number.

643363651 is a deficient number, since it is larger than the sum of its proper divisors (91909101).

643363651 is an equidigital number, since it uses as much as digits as its factorization.

643363651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91909100.

The product of its digits is 116640, while the sum is 37.

The square root of 643363651 is about 25364.6141504262. The cubic root of 643363651 is about 863.2809817873.

The spelling of 643363651 in words is "six hundred forty-three million, three hundred sixty-three thousand, six hundred fifty-one".