66553217 has 2 divisors, whose sum is σ = 66553218. Its totient is φ = 66553216.

The previous prime is 66553189. The next prime is 66553247. The reversal of 66553217 is 71235566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45171841 + 21381376 = 6721^2 + 4624^2 .

It is a cyclic number.

It is not a de Polignac number, because 66553217 - 2⁶ = 66553153 is a prime.

It is not a weakly prime, because it can be changed into another prime (66553247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33276608 + 33276609.

It is an arithmetic number, because the mean of its divisors is an integer number (33276609).

Almost surely, 2^66553217 is an apocalyptic number.

It is an amenable number.

66553217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66553217 is an equidigital number, since it uses as much as digits as its factorization.

66553217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 35.

The square root of 66553217 is about 8158.0155062368. The cubic root of 66553217 is about 405.2499945135.

The spelling of 66553217 in words is "sixty-six million, five hundred fifty-three thousand, two hundred seventeen".