661012169 has 2 divisors, whose sum is σ = 661012170. Its totient is φ = 661012168.

The previous prime is 661012133. The next prime is 661012189. The reversal of 661012169 is 961210166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 582015625 + 78996544 = 24125^2 + 8888^2 .

It is a cyclic number.

It is not a de Polignac number, because 661012169 - 2¹⁶ = 660946633 is a prime.

It is a super-2 number, since 2×661012169² = 873874175132169122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661012129) 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, 330506084 + 330506085.

It is an arithmetic number, because the mean of its divisors is an integer number (330506085).

Almost surely, 2^661012169 is an apocalyptic number.

It is an amenable number.

661012169 is a deficient number, since it is larger than the sum of its proper divisors (1).

661012169 is an equidigital number, since it uses as much as digits as its factorization.

661012169 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 32.

The square root of 661012169 is about 25710.1569228972. The cubic root of 661012169 is about 871.1036194736.

The spelling of 661012169 in words is "six hundred sixty-one million, twelve thousand, one hundred sixty-nine".