618656809 has 6 divisors (see below), whose sum is σ = 657189374. Its totient is φ = 582264960.

The previous prime is 618656803. The next prime is 618656813. The reversal of 618656809 is 908656816.

It can be written as a sum of positive squares in 3 ways, for example, as 381342784 + 237314025 = 19528^2 + 15405^2 .

It is not a de Polignac number, because 618656809 - 2¹¹ = 618654761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (618656803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1070052 + ... + 1070629.

Almost surely, 2^618656809 is an apocalyptic number.

It is an amenable number.

618656809 is a deficient number, since it is larger than the sum of its proper divisors (38532565).

618656809 is a wasteful number, since it uses less digits than its factorization.

618656809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2140715 (or 2140698 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 49.

The square root of 618656809 is about 24872.8126475475. The cubic root of 618656809 is about 852.0856781046.

The spelling of 618656809 in words is "six hundred eighteen million, six hundred fifty-six thousand, eight hundred nine".