618956809 has 2 divisors, whose sum is σ = 618956810. Its totient is φ = 618956808.

The previous prime is 618956797. The next prime is 618956837. The reversal of 618956809 is 908659816.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 449228025 + 169728784 = 21195^2 + 13028^2 .

It is a cyclic number.

It is not a de Polignac number, because 618956809 - 2¹⁷ = 618825737 is a prime.

It is not a weakly prime, because it can be changed into another prime (618956839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309478404 + 309478405.

It is an arithmetic number, because the mean of its divisors is an integer number (309478405).

Almost surely, 2^618956809 is an apocalyptic number.

It is an amenable number.

618956809 is a deficient number, since it is larger than the sum of its proper divisors (1).

618956809 is an equidigital number, since it uses as much as digits as its factorization.

618956809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 52.

The square root of 618956809 is about 24878.8425976772. The cubic root of 618956809 is about 852.2233874082.

The spelling of 618956809 in words is "six hundred eighteen million, nine hundred fifty-six thousand, eight hundred nine".