66865553 has 2 divisors, whose sum is σ = 66865554. Its totient is φ = 66865552.

The previous prime is 66865511. The next prime is 66865583. The reversal of 66865553 is 35556866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46144849 + 20720704 = 6793^2 + 4552^2 .

It is a cyclic number.

It is not a de Polignac number, because 66865553 - 2¹⁶ = 66800017 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66865583) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33432776 + 33432777.

It is an arithmetic number, because the mean of its divisors is an integer number (33432777).

Almost surely, 2^66865553 is an apocalyptic number.

It is an amenable number.

66865553 is a deficient number, since it is larger than the sum of its proper divisors (1).

66865553 is an equidigital number, since it uses as much as digits as its factorization.

66865553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648000, while the sum is 44.

The square root of 66865553 is about 8177.1359900640. The cubic root of 66865553 is about 405.8829550090.

The spelling of 66865553 in words is "sixty-six million, eight hundred sixty-five thousand, five hundred fifty-three".