6631661 has 2 divisors, whose sum is σ = 6631662. Its totient is φ = 6631660.

The previous prime is 6631643. The next prime is 6631663. The reversal of 6631661 is 1661366.

6631661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6375625 + 256036 = 2525^2 + 506^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6631661 is a prime.

Together with 6631663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6631663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3315830 + 3315831.

It is an arithmetic number, because the mean of its divisors is an integer number (3315831).

Almost surely, 2^6631661 is an apocalyptic number.

It is an amenable number.

6631661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6631661 is an equidigital number, since it uses as much as digits as its factorization.

6631661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 6631661 is about 2575.2011571914. The cubic root of 6631661 is about 187.8772115817.

The spelling of 6631661 in words is "six million, six hundred thirty-one thousand, six hundred sixty-one".