661002169 has 2 divisors, whose sum is σ = 661002170. Its totient is φ = 661002168.

The previous prime is 661002137. The next prime is 661002187. The reversal of 661002169 is 961200166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644906025 + 16096144 = 25395^2 + 4012^2 .

It is a cyclic number.

It is not a de Polignac number, because 661002169 - 2⁵ = 661002137 is a prime.

It is a super-2 number, since 2×661002169² = 873847734845409122, which contains 22 as substring.

It is equal to p_34335571 and since 661002169 and 34335571 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661002169.

It is not a weakly prime, because it can be changed into another prime (661002569) 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 as a sum of consecutive naturals, namely, 330501084 + 330501085.

It is an arithmetic number, because the mean of its divisors is an integer number (330501085).

Almost surely, 2^661002169 is an apocalyptic number.

It is an amenable number.

661002169 is a deficient number, since it is larger than the sum of its proper divisors (1).

661002169 is an equidigital number, since it uses as much as digits as its factorization.

661002169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 661002169 is about 25709.9624464914. The cubic root of 661002169 is about 871.0992266749.

The spelling of 661002169 in words is "six hundred sixty-one million, two thousand, one hundred sixty-nine".