643266513 has 12 divisors (see below), whose sum is σ = 929494020. Its totient is φ = 428691456.

The previous prime is 643266511. The next prime is 643266521. The reversal of 643266513 is 315662346.

643266513 is a `hidden beast` number, since 643 + 2 + 6 + 6 + 5 + 1 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 120824064 + 522442449 = 10992^2 + 22857^2 .

It is not a de Polignac number, because 643266513 - 2¹ = 643266511 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (643266511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17745 + ... + 40017.

It is an arithmetic number, because the mean of its divisors is an integer number (77457835).

Almost surely, 2^643266513 is an apocalyptic number.

It is an amenable number.

643266513 is a deficient number, since it is larger than the sum of its proper divisors (286227507).

643266513 is a wasteful number, since it uses less digits than its factorization.

643266513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25488 (or 25485 counting only the distinct ones).

The product of its digits is 77760, while the sum is 36.

The square root of 643266513 is about 25362.6992451513. The cubic root of 643266513 is about 863.2375322242.

The spelling of 643266513 in words is "six hundred forty-three million, two hundred sixty-six thousand, five hundred thirteen".