3945643609 has 4 divisors (see below), whose sum is σ = 3956222116. Its totient is φ = 3935065104.

The previous prime is 3945643571. The next prime is 3945643613. The reversal of 3945643609 is 9063465493.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2444313600 + 1501330009 = 49440^2 + 38747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3945643609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3945643409) 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, 5288694 + ... + 5289439.

It is an arithmetic number, because the mean of its divisors is an integer number (989055529).

Almost surely, 2^3945643609 is an apocalyptic number.

It is an amenable number.

3945643609 is a deficient number, since it is larger than the sum of its proper divisors (10578507).

3945643609 is a wasteful number, since it uses less digits than its factorization.

3945643609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10578506.

The product of its (nonzero) digits is 2099520, while the sum is 49.

The square root of 3945643609 is about 62814.3583028594. The cubic root of 3945643609 is about 1580.1777838990.

The spelling of 3945643609 in words is "three billion, nine hundred forty-five million, six hundred forty-three thousand, six hundred nine".