6440641057 has 4 divisors (see below), whose sum is σ = 6536770096. Its totient is φ = 6344512020.

The previous prime is 6440641027. The next prime is 6440641061. The reversal of 6440641057 is 7501460446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6440641057 - 2¹⁹ = 6440116769 is a prime.

It is a super-2 number, since 2×6440641057² = 82963714450228154498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6440641027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48064419 + ... + 48064552.

It is an arithmetic number, because the mean of its divisors is an integer number (1634192524).

Almost surely, 2^6440641057 is an apocalyptic number.

6440641057 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

6440641057 is a deficient number, since it is larger than the sum of its proper divisors (96129039).

6440641057 is an equidigital number, since it uses as much as digits as its factorization.

6440641057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96129038.

The product of its (nonzero) digits is 80640, while the sum is 37.

The square root of 6440641057 is about 80253.6046355552. The cubic root of 6440641057 is about 1860.5572247505.

The spelling of 6440641057 in words is "six billion, four hundred forty million, six hundred forty-one thousand, fifty-seven".