361661 has 4 divisors (see below), whose sum is σ = 370524. Its totient is φ = 352800.

The previous prime is 361651. The next prime is 361663. The reversal of 361661 is 166163.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166163 = 89 ⋅1867.

It can be written as a sum of positive squares in 2 ways, for example, as 105625 + 256036 = 325^2 + 506^2 .

It is a cyclic number.

It is not a de Polignac number, because 361661 - 2¹⁰ = 360637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (361663) 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, 4370 + ... + 4451.

It is an arithmetic number, because the mean of its divisors is an integer number (92631).

2³⁶¹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

361661 is a deficient number, since it is larger than the sum of its proper divisors (8863).

361661 is an equidigital number, since it uses as much as digits as its factorization.

361661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8862.

The product of its digits is 648, while the sum is 23.

The square root of 361661 is about 601.3825737415. The cubic root of 361661 is about 71.2471056586.

The spelling of 361661 in words is "three hundred sixty-one thousand, six hundred sixty-one".