66299621 has 2 divisors, whose sum is σ = 66299622. Its totient is φ = 66299620.

The previous prime is 66299617. The next prime is 66299633. The reversal of 66299621 is 12699266.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56776225 + 9523396 = 7535^2 + 3086^2 .

It is a cyclic number.

It is not a de Polignac number, because 66299621 - 2² = 66299617 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66299641) 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, 33149810 + 33149811.

It is an arithmetic number, because the mean of its divisors is an integer number (33149811).

Almost surely, 2^66299621 is an apocalyptic number.

It is an amenable number.

66299621 is a deficient number, since it is larger than the sum of its proper divisors (1).

66299621 is an equidigital number, since it uses as much as digits as its factorization.

66299621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 66299621 is about 8142.4579212913. The cubic root of 66299621 is about 404.7346145342.

The spelling of 66299621 in words is "sixty-six million, two hundred ninety-nine thousand, six hundred twenty-one".