66553321 has 2 divisors, whose sum is σ = 66553322. Its totient is φ = 66553320.

The previous prime is 66553303. The next prime is 66553327. The reversal of 66553321 is 12335566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65028096 + 1525225 = 8064^2 + 1235^2 .

It is a cyclic number.

It is not a de Polignac number, because 66553321 - 2⁹ = 66552809 is a prime.

It is a super-2 number, since 2×66553321² = 8858689072258082, which contains 22 as substring.

It is a Chen prime.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (66553327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33276660 + 33276661.

It is an arithmetic number, because the mean of its divisors is an integer number (33276661).

Almost surely, 2^66553321 is an apocalyptic number.

It is an amenable number.

66553321 is a deficient number, since it is larger than the sum of its proper divisors (1).

66553321 is an equidigital number, since it uses as much as digits as its factorization.

66553321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 31.

The square root of 66553321 is about 8158.0218803335. The cubic root of 66553321 is about 405.2502056026.

Adding to 66553321 its reverse (12335566), we get a palindrome (78888887).

The spelling of 66553321 in words is "sixty-six million, five hundred fifty-three thousand, three hundred twenty-one".