1966561 has 2 divisors, whose sum is σ = 1966562. Its totient is φ = 1966560.

The previous prime is 1966511. The next prime is 1966583. The reversal of 1966561 is 1656691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1960000 + 6561 = 1400^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 1966561 - 2⁹ = 1966049 is a prime.

It is not a weakly prime, because it can be changed into another prime (1966511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 983280 + 983281.

It is an arithmetic number, because the mean of its divisors is an integer number (983281).

2^1966561 is an apocalyptic number.

It is an amenable number.

1966561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1966561 is an equidigital number, since it uses as much as digits as its factorization.

1966561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 34.

The square root of 1966561 is about 1402.3412566134. The cubic root of 1966561 is about 125.2859798917.

It can be divided in two parts, 196 and 6561, that multiplied together give a square (1285956 = 1134²).

The spelling of 1966561 in words is "one million, nine hundred sixty-six thousand, five hundred sixty-one".