645543513 has 10 divisors (see below), whose sum is σ = 964330554. Its totient is φ = 430362288.

The previous prime is 645543511. The next prime is 645543517. The reversal of 645543513 is 315345546.

645543513 is a `hidden beast` number, since 64 + 5 + 543 + 51 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 349428249 + 296115264 = 18693^2 + 17208^2 .

It is not a de Polignac number, because 645543513 - 2¹ = 645543511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645543511) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3984756 + ... + 3984917.

Almost surely, 2^645543513 is an apocalyptic number.

It is an amenable number.

645543513 is a deficient number, since it is larger than the sum of its proper divisors (318787041).

645543513 is an equidigital number, since it uses as much as digits as its factorization.

645543513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7969685 (or 7969676 counting only the distinct ones).

The product of its digits is 108000, while the sum is 36.

The square root of 645543513 is about 25407.5483468988. The cubic root of 645543513 is about 864.2548799535.

The spelling of 645543513 in words is "six hundred forty-five million, five hundred forty-three thousand, five hundred thirteen".