6645839540 has 24 divisors (see below), whose sum is σ = 14014667520. Its totient is φ = 2647211168.

The previous prime is 6645839539. The next prime is 6645839567. The reversal of 6645839540 is 459385466.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 690392 + ... + 699951.

It is an arithmetic number, because the mean of its divisors is an integer number (583944480).

Almost surely, 2^6645839540 is an apocalyptic number.

It is an amenable number.

6645839540 is an abundant number, since it is smaller than the sum of its proper divisors (7368827980).

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

6645839540 is a wasteful number, since it uses less digits than its factorization.

6645839540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1390591 (or 1390589 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 50.

The square root of 6645839540 is about 81522.0187434045. The cubic root of 6645839540 is about 1880.1101055930.

The spelling of 6645839540 in words is "six billion, six hundred forty-five million, eight hundred thirty-nine thousand, five hundred forty".