66454561 has 2 divisors, whose sum is σ = 66454562. Its totient is φ = 66454560.

The previous prime is 66454529. The next prime is 66454579. The reversal of 66454561 is 16545466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65610000 + 844561 = 8100^2 + 919^2 .

It is a cyclic number.

It is not a de Polignac number, because 66454561 - 2⁵ = 66454529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66454561.

It is not a weakly prime, because it can be changed into another prime (66454501) 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, 33227280 + 33227281.

It is an arithmetic number, because the mean of its divisors is an integer number (33227281).

Almost surely, 2^66454561 is an apocalyptic number.

It is an amenable number.

66454561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66454561 is an equidigital number, since it uses as much as digits as its factorization.

66454561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86400, while the sum is 37.

The square root of 66454561 is about 8151.9666952215. The cubic root of 66454561 is about 405.0496530090.

It can be divided in two parts, 664 and 54561, that added together give a square (55225 = 235²).

The spelling of 66454561 in words is "sixty-six million, four hundred fifty-four thousand, five hundred sixty-one".