1664251 has 2 divisors, whose sum is σ = 1664252. Its totient is φ = 1664250.

The previous prime is 1664227. The next prime is 1664261. The reversal of 1664251 is 1524661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1664251 - 2⁷ = 1664123 is a prime.

1664251 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1664261) 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, 832125 + 832126.

It is an arithmetic number, because the mean of its divisors is an integer number (832126).

2^1664251 is an apocalyptic number.

1664251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664251 is an equidigital number, since it uses as much as digits as its factorization.

1664251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 1664251 is about 1290.0585258042. The cubic root of 1664251 is about 118.5058006620.

The spelling of 1664251 in words is "one million, six hundred sixty-four thousand, two hundred fifty-one".