6440645570 has 8 divisors (see below), whose sum is σ = 11593162044. Its totient is φ = 2576258224.

The previous prime is 6440645557. The next prime is 6440645579. The reversal of 6440645570 is 755460446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6006715009 + 433930561 = 77503^2 + 20831^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6440645579) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322032269 + ... + 322032288.

Almost surely, 2^6440645570 is an apocalyptic number.

6440645570 is a deficient number, since it is larger than the sum of its proper divisors (5152516474).

6440645570 is a wasteful number, since it uses less digits than its factorization.

6440645570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 644064564.

The product of its (nonzero) digits is 403200, while the sum is 41.

The square root of 6440645570 is about 80253.6327526673. The cubic root of 6440645570 is about 1860.5576593186.

The spelling of 6440645570 in words is "six billion, four hundred forty million, six hundred forty-five thousand, five hundred seventy".