1091645557 has 2 divisors, whose sum is σ = 1091645558. Its totient is φ = 1091645556.

The previous prime is 1091645549. The next prime is 1091645561. The reversal of 1091645557 is 7555461901.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 778744836 + 312900721 = 27906^2 + 17689^2 .

It is a cyclic number.

It is not a de Polignac number, because 1091645557 - 2³ = 1091645549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1091645507) 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, 545822778 + 545822779.

It is an arithmetic number, because the mean of its divisors is an integer number (545822779).

Almost surely, 2^1091645557 is an apocalyptic number.

It is an amenable number.

1091645557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091645557 is an equidigital number, since it uses as much as digits as its factorization.

1091645557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 189000, while the sum is 43.

The square root of 1091645557 is about 33040.0598819070. The cubic root of 1091645557 is about 1029.6600999294.

The spelling of 1091645557 in words is "one billion, ninety-one million, six hundred forty-five thousand, five hundred fifty-seven".