643157759 has 4 divisors (see below), whose sum is σ = 643413216. Its totient is φ = 642902304.

The previous prime is 643157747. The next prime is 643157777. The reversal of 643157759 is 957751346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643157759 - 2¹² = 643153663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643157059) 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, 123914 + ... + 128999.

It is an arithmetic number, because the mean of its divisors is an integer number (160853304).

Almost surely, 2^643157759 is an apocalyptic number.

643157759 is a deficient number, since it is larger than the sum of its proper divisors (255457).

643157759 is a wasteful number, since it uses less digits than its factorization.

643157759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255456.

The product of its digits is 793800, while the sum is 47.

The square root of 643157759 is about 25360.5551792543. Note that the first 3 decimals coincide. The cubic root of 643157759 is about 863.1888816655.

The spelling of 643157759 in words is "six hundred forty-three million, one hundred fifty-seven thousand, seven hundred fifty-nine".