6440640532 has 12 divisors (see below), whose sum is σ = 11387318740. Its totient is φ = 3187120896.

The previous prime is 6440640529. The next prime is 6440640571. The reversal of 6440640532 is 2350460446.

It can be written as a sum of positive squares in 2 ways, for example, as 2319770896 + 4120869636 = 48164^2 + 64194^2 .

It is a congruent number.

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, 8299407 + ... + 8300182.

Almost surely, 2^6440640532 is an apocalyptic number.

It is an amenable number.

6440640532 is a deficient number, since it is larger than the sum of its proper divisors (4946678208).

6440640532 is a wasteful number, since it uses less digits than its factorization.

6440640532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16599690 (or 16599688 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 34.

The square root of 6440640532 is about 80253.6013646740. The cubic root of 6440640532 is about 1860.5571741969.

The spelling of 6440640532 in words is "six billion, four hundred forty million, six hundred forty thousand, five hundred thirty-two".