1591663 has 2 divisors, whose sum is σ = 1591664. Its totient is φ = 1591662.

The previous prime is 1591637. The next prime is 1591697. The reversal of 1591663 is 3661951.

It is a weak prime.

It is an emirp because it is prime and its reverse (3661951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1591663 - 2⁵ = 1591631 is a prime.

It is a super-2 number, since 2×1591663² = 5066782211138, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1591363) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 795831 + 795832.

It is an arithmetic number, because the mean of its divisors is an integer number (795832).

2^1591663 is an apocalyptic number.

1591663 is a deficient number, since it is larger than the sum of its proper divisors (1).

1591663 is an equidigital number, since it uses as much as digits as its factorization.

1591663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 31.

The square root of 1591663 is about 1261.6112713510. The cubic root of 1591663 is about 116.7572095318.

The spelling of 1591663 in words is "one million, five hundred ninety-one thousand, six hundred sixty-three".