1664071 has 2 divisors, whose sum is σ = 1664072. Its totient is φ = 1664070.

The previous prime is 1664063. The next prime is 1664083. The reversal of 1664071 is 1704661.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1664071 - 2³ = 1664063 is a prime.

1664071 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1664021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832035 + 832036.

It is an arithmetic number, because the mean of its divisors is an integer number (832036).

2^1664071 is an apocalyptic number.

1664071 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664071 is an equidigital number, since it uses as much as digits as its factorization.

1664071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 1664071 is about 1289.9887596410. The cubic root of 1664071 is about 118.5015281067.

The spelling of 1664071 in words is "one million, six hundred sixty-four thousand, seventy-one".