123661 has 2 divisors, whose sum is σ = 123662. Its totient is φ = 123660.

The previous prime is 123653. The next prime is 123667. The reversal of 123661 is 166321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81225 + 42436 = 285^2 + 206^2 .

It is a cyclic number.

It is not a de Polignac number, because 123661 - 2³ = 123653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61830 + 61831.

It is an arithmetic number, because the mean of its divisors is an integer number (61831).

2¹²³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

123661 is a deficient number, since it is larger than the sum of its proper divisors (1).

123661 is an equidigital number, since it uses as much as digits as its factorization.

123661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 19.

The square root of 123661 is about 351.6546601426. The cubic root of 123661 is about 49.8208253626.

Adding to 123661 its reverse (166321), we get a palindrome (289982).

It can be divided in two parts, 123 and 661, that added together give a square (784 = 28²).

The spelling of 123661 in words is "one hundred twenty-three thousand, six hundred sixty-one".