1666604593 has 2 divisors, whose sum is σ = 1666604594. Its totient is φ = 1666604592.

The previous prime is 1666604591. The next prime is 1666604677. The reversal of 1666604593 is 3954066661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1575057969 + 91546624 = 39687^2 + 9568^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666604593 - 2¹ = 1666604591 is a prime.

Together with 1666604591, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1666604591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833302296 + 833302297.

It is an arithmetic number, because the mean of its divisors is an integer number (833302297).

Almost surely, 2^1666604593 is an apocalyptic number.

It is an amenable number.

1666604593 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666604593 is an equidigital number, since it uses as much as digits as its factorization.

1666604593 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 699840, while the sum is 46.

The square root of 1666604593 is about 40824.0687952585. The cubic root of 1666604593 is about 1185.6163820200.

The spelling of 1666604593 in words is "one billion, six hundred sixty-six million, six hundred four thousand, five hundred ninety-three".