6398740640 has 24 divisors (see below), whose sum is σ = 15117025140. Its totient is φ = 2559496192.

The previous prime is 6398740633. The next prime is 6398740679. The reversal of 6398740640 is 460478936.

It can be written as a sum of positive squares in 2 ways, for example, as 5887799824 + 510940816 = 76732^2 + 22604^2 .

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, 19995905 + ... + 19996224.

Almost surely, 2^6398740640 is an apocalyptic number.

It is an amenable number.

6398740640 is an abundant number, since it is smaller than the sum of its proper divisors (8718284500).

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

6398740640 is a wasteful number, since it uses less digits than its factorization.

6398740640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39992144 (or 39992136 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 47.

The square root of 6398740640 is about 79992.1286127579. The cubic root of 6398740640 is about 1856.5137456375.

The spelling of 6398740640 in words is "six billion, three hundred ninety-eight million, seven hundred forty thousand, six hundred forty".