643260505 has 16 divisors (see below), whose sum is σ = 777014784. Its totient is φ = 511220160.

The previous prime is 643260493. The next prime is 643260511. The reversal of 643260505 is 505062346.

It is not a de Polignac number, because 643260505 - 2¹⁹ = 642736217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 884452 + ... + 885178.

It is an arithmetic number, because the mean of its divisors is an integer number (48563424).

Almost surely, 2^643260505 is an apocalyptic number.

It is an amenable number.

643260505 is a deficient number, since it is larger than the sum of its proper divisors (133754279).

643260505 is a wasteful number, since it uses less digits than its factorization.

643260505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1656.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 643260505 is about 25362.5808032227. The cubic root of 643260505 is about 863.2348447185.

The spelling of 643260505 in words is "six hundred forty-three million, two hundred sixty thousand, five hundred five".