64440404240 has 20 divisors (see below), whose sum is σ = 149823940044. Its totient is φ = 25776161664.

The previous prime is 64440404207. The next prime is 64440404243. The reversal of 64440404240 is 4240404446.

It can be written as a sum of positive squares in 2 ways, for example, as 19726764304 + 44713639936 = 140452^2 + 211456^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×64440404240² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 64440404197 and 64440404206.

It is not an unprimeable number, because it can be changed into a prime (64440404243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 402752447 + ... + 402752606.

Almost surely, 2^64440404240 is an apocalyptic number.

It is an amenable number.

64440404240 is an abundant number, since it is smaller than the sum of its proper divisors (85383535804).

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

64440404240 is a wasteful number, since it uses less digits than its factorization.

64440404240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805505066 (or 805505060 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 32.

Adding to 64440404240 its reverse (4240404446), we get a palindrome (68680808686).

The spelling of 64440404240 in words is "sixty-four billion, four hundred forty million, four hundred four thousand, two hundred forty".