661118569 has 2 divisors, whose sum is σ = 661118570. Its totient is φ = 661118568.

The previous prime is 661118537. The next prime is 661118573. The reversal of 661118569 is 965811166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 501222544 + 159896025 = 22388^2 + 12645^2 .

It is a cyclic number.

It is not a de Polignac number, because 661118569 - 2⁵ = 661118537 is a prime.

It is a super-2 number, since 2×661118569² = 874155524553215522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (661118599) 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, 330559284 + 330559285.

It is an arithmetic number, because the mean of its divisors is an integer number (330559285).

Almost surely, 2^661118569 is an apocalyptic number.

It is an amenable number.

661118569 is a deficient number, since it is larger than the sum of its proper divisors (1).

661118569 is an equidigital number, since it uses as much as digits as its factorization.

661118569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 43.

The square root of 661118569 is about 25712.2260607673. The cubic root of 661118569 is about 871.1503561081.

The spelling of 661118569 in words is "six hundred sixty-one million, one hundred eighteen thousand, five hundred sixty-nine".