6609781 has 2 divisors, whose sum is σ = 6609782. Its totient is φ = 6609780.

The previous prime is 6609769. The next prime is 6609793. The reversal of 6609781 is 1879066.

6609781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (6609769) and next prime (6609793).

It can be written as a sum of positive squares in only one way, i.e., 4691556 + 1918225 = 2166^2 + 1385^2 .

It is a cyclic number.

It is not a de Polignac number, because 6609781 - 2¹⁵ = 6577013 is a prime.

It is a super-2 number, since 2×6609781² = 87378409735922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 6609781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6609761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3304890 + 3304891.

It is an arithmetic number, because the mean of its divisors is an integer number (3304891).

Almost surely, 2^6609781 is an apocalyptic number.

It is an amenable number.

6609781 is a deficient number, since it is larger than the sum of its proper divisors (1).

6609781 is an equidigital number, since it uses as much as digits as its factorization.

6609781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 6609781 is about 2570.9494355199. The cubic root of 6609781 is about 187.6703613121.

The spelling of 6609781 in words is "six million, six hundred nine thousand, seven hundred eighty-one".