6499861 has 2 divisors, whose sum is σ = 6499862. Its totient is φ = 6499860.

The previous prime is 6499859. The next prime is 6499879. The reversal of 6499861 is 1689946.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4452100 + 2047761 = 2110^2 + 1431^2 .

It is a cyclic number.

It is not a de Polignac number, because 6499861 - 2¹ = 6499859 is a prime.

Together with 6499859, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6499841) 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 as a sum of consecutive naturals, namely, 3249930 + 3249931.

It is an arithmetic number, because the mean of its divisors is an integer number (3249931).

Almost surely, 2^6499861 is an apocalyptic number.

It is an amenable number.

6499861 is a deficient number, since it is larger than the sum of its proper divisors (1).

6499861 is an equidigital number, since it uses as much as digits as its factorization.

6499861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 43.

The square root of 6499861 is about 2549.4824965079. The cubic root of 6499861 is about 186.6242275261.

The spelling of 6499861 in words is "six million, four hundred ninety-nine thousand, eight hundred sixty-one".