6537661 has 12 divisors (see below), whose sum is σ = 7224028. Its totient is φ = 5880384.

The previous prime is 6537649. The next prime is 6537667. The reversal of 6537661 is 1667356.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2232036 + 4305625 = 1494^2 + 2075^2 .

It is not a de Polignac number, because 6537661 - 2¹³ = 6529469 is a prime.

It is a super-2 number, since 2×6537661² = 85482022701842, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (22680) is a multiple of the sum of its prime factors (252).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6537667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 78726 + ... + 78808.

Almost surely, 2^6537661 is an apocalyptic number.

It is an amenable number.

6537661 is a deficient number, since it is larger than the sum of its proper divisors (686367).

6537661 is an equidigital number, since it uses as much as digits as its factorization.

6537661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252 (or 169 counting only the distinct ones).

The product of its digits is 22680, while the sum is 34.

The square root of 6537661 is about 2556.8850189244. The cubic root of 6537661 is about 186.9853001113.

The spelling of 6537661 in words is "six million, five hundred thirty-seven thousand, six hundred sixty-one".