1665997 has 2 divisors, whose sum is σ = 1665998. Its totient is φ = 1665996.

The previous prime is 1665973. The next prime is 1666003. The reversal of 1665997 is 7995661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 866761 + 799236 = 931^2 + 894^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665997 - 2⁷ = 1665869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665907) 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, 832998 + 832999.

It is an arithmetic number, because the mean of its divisors is an integer number (832999).

2^1665997 is an apocalyptic number.

It is an amenable number.

1665997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665997 is an equidigital number, since it uses as much as digits as its factorization.

1665997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 102060, while the sum is 43.

The square root of 1665997 is about 1290.7350618930. The cubic root of 1665997 is about 118.5472284698.

It can be divided in two parts, 1665 and 997, that added together give a palindrome (2662).

The spelling of 1665997 in words is "one million, six hundred sixty-five thousand, nine hundred ninety-seven".