1664447 has 2 divisors, whose sum is σ = 1664448. Its totient is φ = 1664446.

The previous prime is 1664437. The next prime is 1664459. The reversal of 1664447 is 7444661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1664447 - 2⁴ = 1664431 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1664407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832223 + 832224.

It is an arithmetic number, because the mean of its divisors is an integer number (832224).

2^1664447 is an apocalyptic number.

1664447 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664447 is an equidigital number, since it uses as much as digits as its factorization.

1664447 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 32.

The square root of 1664447 is about 1290.1344891134. The cubic root of 1664447 is about 118.5104526496.

The spelling of 1664447 in words is "one million, six hundred sixty-four thousand, four hundred forty-seven".