6691631 has 2 divisors, whose sum is σ = 6691632. Its totient is φ = 6691630.

The previous prime is 6691613. The next prime is 6691637. The reversal of 6691631 is 1361966.

Together with previous prime (6691613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6691631 - 2¹⁸ = 6429487 is a prime.

It is a super-2 number, since 2×6691631² = 89555850880322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6691637) 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 as a sum of consecutive naturals, namely, 3345815 + 3345816.

It is an arithmetic number, because the mean of its divisors is an integer number (3345816).

Almost surely, 2^6691631 is an apocalyptic number.

6691631 is a deficient number, since it is larger than the sum of its proper divisors (1).

6691631 is an equidigital number, since it uses as much as digits as its factorization.

6691631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832, while the sum is 32.

The square root of 6691631 is about 2586.8187025766. The cubic root of 6691631 is about 188.4418365205.

The spelling of 6691631 in words is "six million, six hundred ninety-one thousand, six hundred thirty-one".