1664857 has 2 divisors, whose sum is σ = 1664858. Its totient is φ = 1664856.

The previous prime is 1664849. The next prime is 1664863. The reversal of 1664857 is 7584661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1565001 + 99856 = 1251^2 + 316^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664857 - 2³ = 1664849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664807) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832428 + 832429.

It is an arithmetic number, because the mean of its divisors is an integer number (832429).

2^1664857 is an apocalyptic number.

It is an amenable number.

1664857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664857 is an equidigital number, since it uses as much as digits as its factorization.

1664857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 37.

The square root of 1664857 is about 1290.2933774921. The cubic root of 1664857 is about 118.5201826674.

The spelling of 1664857 in words is "one million, six hundred sixty-four thousand, eight hundred fifty-seven".