1591491553 has 2 divisors, whose sum is σ = 1591491554. Its totient is φ = 1591491552.

The previous prime is 1591491541. The next prime is 1591491563. The reversal of 1591491553 is 3551941951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1520376064 + 71115489 = 38992^2 + 8433^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1591491553 is a prime.

It is not a weakly prime, because it can be changed into another prime (1591491563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 795745776 + 795745777.

It is an arithmetic number, because the mean of its divisors is an integer number (795745777).

Almost surely, 2^1591491553 is an apocalyptic number.

It is an amenable number.

1591491553 is a deficient number, since it is larger than the sum of its proper divisors (1).

1591491553 is an equidigital number, since it uses as much as digits as its factorization.

1591491553 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 121500, while the sum is 43.

The square root of 1591491553 is about 39893.5026414077. The cubic root of 1591491553 is about 1167.5301718868.

The spelling of 1591491553 in words is "one billion, five hundred ninety-one million, four hundred ninety-one thousand, five hundred fifty-three".