661169 has 4 divisors (see below), whose sum is σ = 663396. Its totient is φ = 658944.

The previous prime is 661139. The next prime is 661183. The reversal of 661169 is 961166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 961166 = 2 ⋅480583.

It can be written as a sum of positive squares in 2 ways, for example, as 113569 + 547600 = 337^2 + 740^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661169 is a prime.

It is a super-2 number, since 2×661169² = 874288893122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 584 + ... + 1289.

It is an arithmetic number, because the mean of its divisors is an integer number (165849).

2⁶⁶¹¹⁶⁹ is an apocalyptic number.

It is an amenable number.

661169 is a deficient number, since it is larger than the sum of its proper divisors (2227).

661169 is a wasteful number, since it uses less digits than its factorization.

661169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2226.

The product of its digits is 1944, while the sum is 29.

The square root of 661169 is about 813.1229919268. The cubic root of 661169 is about 87.1172506379.

The spelling of 661169 in words is "six hundred sixty-one thousand, one hundred sixty-nine".