6505661 has 4 divisors (see below), whose sum is σ = 6534300. Its totient is φ = 6477024.

The previous prime is 6505649. The next prime is 6505663. The reversal of 6505661 is 1665056.

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 5262436 + 1243225 = 2294^2 + 1115^2 .

It is a cyclic number.

It is not a de Polignac number, because 6505661 - 2¹⁴ = 6489277 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 (6505663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13976 + ... + 14433.

It is an arithmetic number, because the mean of its divisors is an integer number (1633575).

Almost surely, 2^6505661 is an apocalyptic number.

It is an amenable number.

6505661 is a deficient number, since it is larger than the sum of its proper divisors (28639).

6505661 is a wasteful number, since it uses less digits than its factorization.

6505661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28638.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 6505661 is about 2550.6197286150. The cubic root of 6505661 is about 186.6797209550.

The spelling of 6505661 in words is "six million, five hundred five thousand, six hundred sixty-one".