6440921290 has 8 divisors (see below), whose sum is σ = 11593658340. Its totient is φ = 2576368512.

The previous prime is 6440921273. The next prime is 6440921299. The reversal of 6440921290 is 921290446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6133865761 + 307055529 = 78319^2 + 17523^2 .

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

It is not an unprimeable number, because it can be changed into a prime (6440921299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 322046055 + ... + 322046074.

Almost surely, 2^6440921290 is an apocalyptic number.

6440921290 is a deficient number, since it is larger than the sum of its proper divisors (5152737050).

6440921290 is a wasteful number, since it uses less digits than its factorization.

6440921290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644092136.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 6440921290 is about 80255.3505381417. The cubic root of 6440921290 is about 1860.5842087089.

The spelling of 6440921290 in words is "six billion, four hundred forty million, nine hundred twenty-one thousand, two hundred ninety".