3945643686440 has 64 divisors (see below), whose sum is σ = 8900978708160. Its totient is φ = 1574119756800.

The previous prime is 3945643686407. The next prime is 3945643686469. The reversal of 3945643686440 is 446863465493.

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, 225882587 + ... + 225900053.

It is an arithmetic number, because the mean of its divisors is an integer number (139077792315).

Almost surely, 2^{3945643686440} is an apocalyptic number.

It is an amenable number.

3945643686440 is an abundant number, since it is smaller than the sum of its proper divisors (4955335021720).

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

3945643686440 is a wasteful number, since it uses less digits than its factorization.

3945643686440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31962 (or 31958 counting only the distinct ones).

The product of its (nonzero) digits is 179159040, while the sum is 62.

The spelling of 3945643686440 in words is "three trillion, nine hundred forty-five billion, six hundred forty-three million, six hundred eighty-six thousand, four hundred forty".