666437 has 2 divisors, whose sum is σ = 666438. Its totient is φ = 666436.

The previous prime is 666433. The next prime is 666439. The reversal of 666437 is 734666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 591361 + 75076 = 769^2 + 274^2 .

It is a cyclic number.

It is not a de Polignac number, because 666437 - 2² = 666433 is a prime.

Together with 666439, 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 (666431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333218 + 333219.

It is an arithmetic number, because the mean of its divisors is an integer number (333219).

2⁶⁶⁶⁴³⁷ is an apocalyptic number.

It is an amenable number.

666437 is a deficient number, since it is larger than the sum of its proper divisors (1).

666437 is an equidigital number, since it uses as much as digits as its factorization.

666437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 32.

The square root of 666437 is about 816.3559272768. The cubic root of 666437 is about 87.3480137058.

The spelling of 666437 in words is "six hundred sixty-six thousand, four hundred thirty-seven".