6440557 has 4 divisors (see below), whose sum is σ = 6449436. Its totient is φ = 6431680.

The previous prime is 6440549. The next prime is 6440561. The reversal of 6440557 is 7550446.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2653641 + 3786916 = 1629^2 + 1946^2 .

It is a cyclic number.

It is not a de Polignac number, because 6440557 - 2³ = 6440549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3244 + ... + 4837.

It is an arithmetic number, because the mean of its divisors is an integer number (1612359).

Almost surely, 2^6440557 is an apocalyptic number.

It is an amenable number.

6440557 is a deficient number, since it is larger than the sum of its proper divisors (8879).

6440557 is an equidigital number, since it uses as much as digits as its factorization.

6440557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8878.

The product of its (nonzero) digits is 16800, while the sum is 31.

The square root of 6440557 is about 2537.8252500911. The cubic root of 6440557 is about 186.0549130653.

The spelling of 6440557 in words is "six million, four hundred forty thousand, five hundred fifty-seven".