661161 has 8 divisors (see below), whose sum is σ = 893920. Its totient is φ = 434592.

The previous prime is 661139. The next prime is 661183. The reversal of 661161 is 161166.

It is an interprime number because it is at equal distance from previous prime (661139) and next prime (661183).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661161 - 2⁶ = 661097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (661121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1291 + ... + 1728.

It is an arithmetic number, because the mean of its divisors is an integer number (111740).

2⁶⁶¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

661161 is a deficient number, since it is larger than the sum of its proper divisors (232759).

661161 is a wasteful number, since it uses less digits than its factorization.

661161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3095.

The product of its digits is 216, while the sum is 21.

The square root of 661161 is about 813.1180726069. The cubic root of 661161 is about 87.1168992700.

The spelling of 661161 in words is "six hundred sixty-one thousand, one hundred sixty-one".