66787121 has 2 divisors, whose sum is σ = 66787122. Its totient is φ = 66787120.

The previous prime is 66787093. The next prime is 66787129. The reversal of 66787121 is 12178766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56776225 + 10010896 = 7535^2 + 3164^2 .

It is a cyclic number.

It is not a de Polignac number, because 66787121 - 2⁶ = 66787057 is a prime.

It is not a weakly prime, because it can be changed into another prime (66787129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33393560 + 33393561.

It is an arithmetic number, because the mean of its divisors is an integer number (33393561).

Almost surely, 2^66787121 is an apocalyptic number.

It is an amenable number.

66787121 is a deficient number, since it is larger than the sum of its proper divisors (1).

66787121 is an equidigital number, since it uses as much as digits as its factorization.

66787121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 38.

The square root of 66787121 is about 8172.3387717348. The cubic root of 66787121 is about 405.7241953009.

The spelling of 66787121 in words is "sixty-six million, seven hundred eighty-seven thousand, one hundred twenty-one".