145661 has 2 divisors, whose sum is σ = 145662. Its totient is φ = 145660.

The previous prime is 145643. The next prime is 145679. The reversal of 145661 is 166541.

It is a balanced prime because it is at equal distance from previous prime (145643) and next prime (145679).

It can be written as a sum of positive squares in only one way, i.e., 109561 + 36100 = 331^2 + 190^2 .

It is an emirp because it is prime and its reverse (166541) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 145661 - 2¹⁴ = 129277 is a prime.

It is a Chen prime.

It is equal to p₁₃₄₇₈ and since 145661 and 13478 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 7.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72830 + 72831.

It is an arithmetic number, because the mean of its divisors is an integer number (72831).

2¹⁴⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

145661 is a deficient number, since it is larger than the sum of its proper divisors (1).

145661 is an equidigital number, since it uses as much as digits as its factorization.

145661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 23.

The square root of 145661 is about 381.6556039154. The cubic root of 145661 is about 52.6155881070.

The spelling of 145661 in words is "one hundred forty-five thousand, six hundred sixty-one".