6643896464 has 20 divisors (see below), whose sum is σ = 12879358704. Its totient is φ = 3320191008.

The previous prime is 6643896451. The next prime is 6643896473. The reversal of 6643896464 is 4646983466.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78362 + ... + 139385.

Almost surely, 2^6643896464 is an apocalyptic number.

It is an amenable number.

6643896464 is a deficient number, since it is larger than the sum of its proper divisors (6235462240).

6643896464 is a wasteful number, since it uses less digits than its factorization.

6643896464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219662 (or 219656 counting only the distinct ones).

The product of its digits is 17915904, while the sum is 56.

The square root of 6643896464 is about 81510.1003802596. The cubic root of 6643896464 is about 1879.9268554612.

The spelling of 6643896464 in words is "six billion, six hundred forty-three million, eight hundred ninety-six thousand, four hundred sixty-four".