618728557 has 2 divisors, whose sum is σ = 618728558. Its totient is φ = 618728556.

The previous prime is 618728507. The next prime is 618728567. The reversal of 618728557 is 755827816.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 610781796 + 7946761 = 24714^2 + 2819^2 .

It is a cyclic number.

It is not a de Polignac number, because 618728557 - 2¹⁵ = 618695789 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 618728557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (618728507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309364278 + 309364279.

It is an arithmetic number, because the mean of its divisors is an integer number (309364279).

Almost surely, 2^618728557 is an apocalyptic number.

It is an amenable number.

618728557 is a deficient number, since it is larger than the sum of its proper divisors (1).

618728557 is an equidigital number, since it uses as much as digits as its factorization.

618728557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 940800, while the sum is 49.

The square root of 618728557 is about 24874.2549034137. The cubic root of 618728557 is about 852.1186167113.

The spelling of 618728557 in words is "six hundred eighteen million, seven hundred twenty-eight thousand, five hundred fifty-seven".