6440561 has 2 divisors, whose sum is σ = 6440562. Its totient is φ = 6440560.

The previous prime is 6440549. The next prime is 6440579. The reversal of 6440561 is 1650446.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5664400 + 776161 = 2380^2 + 881^2 .

It is a cyclic number.

It is not a de Polignac number, because 6440561 - 2¹⁴ = 6424177 is a prime.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 6440561.

It is not a weakly prime, because it can be changed into another prime (6410561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3220280 + 3220281.

It is an arithmetic number, because the mean of its divisors is an integer number (3220281).

Almost surely, 2^6440561 is an apocalyptic number.

It is an amenable number.

6440561 is a deficient number, since it is larger than the sum of its proper divisors (1).

6440561 is an equidigital number, since it uses as much as digits as its factorization.

6440561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 6440561 is about 2537.8260381673. The cubic root of 6440561 is about 186.0549515826.

The spelling of 6440561 in words is "six million, four hundred forty thousand, five hundred sixty-one".