660731 has 2 divisors, whose sum is σ = 660732. Its totient is φ = 660730.

The previous prime is 660727. The next prime is 660733. The reversal of 660731 is 137066.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 660731 - 2² = 660727 is a prime.

It is a super-2 number, since 2×660731² = 873130908722, which contains 22 as substring.

Together with 660733, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 660697 and 660706.

It is not a weakly prime, because it can be changed into another prime (660733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330365 + 330366.

It is an arithmetic number, because the mean of its divisors is an integer number (330366).

2⁶⁶⁰⁷³¹ is an apocalyptic number.

660731 is a deficient number, since it is larger than the sum of its proper divisors (1).

660731 is an equidigital number, since it uses as much as digits as its factorization.

660731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 660731 is about 812.8536153576. The cubic root of 660731 is about 87.0980090699.

Adding to 660731 its reverse (137066), we get a palindrome (797797).

The spelling of 660731 in words is "six hundred sixty thousand, seven hundred thirty-one".