3945643644 has 48 divisors (see below), whose sum is σ = 9376012800. Its totient is φ = 1291063296.

The previous prime is 3945643621. The next prime is 3945643673. The reversal of 3945643644 is 4463465493.

It is a junction number, because it is equal to n+sod(n) for n = 3945643593 and 3945643602.

It is a congruent 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, 540829 + ... + 548075.

It is an arithmetic number, because the mean of its divisors is an integer number (195333600).

Almost surely, 2^3945643644 is an apocalyptic number.

It is an amenable number.

3945643644 is an abundant number, since it is smaller than the sum of its proper divisors (5430369156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3945643644 is a wasteful number, since it uses less digits than its factorization.

3945643644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8082 (or 8080 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 48.

The square root of 3945643644 is about 62814.3585814581. The cubic root of 3945643644 is about 1580.1777885714.

The spelling of 3945643644 in words is "three billion, nine hundred forty-five million, six hundred forty-three thousand, six hundred forty-four".