66650401 has 2 divisors, whose sum is σ = 66650402. Its totient is φ = 66650400.

The previous prime is 66650383. The next prime is 66650443. The reversal of 66650401 is 10405666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66438801 + 211600 = 8151^2 + 460^2 .

It is a cyclic number.

It is not a de Polignac number, because 66650401 - 2⁹ = 66649889 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66650401.

It is not a weakly prime, because it can be changed into another prime (66650501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33325200 + 33325201.

It is an arithmetic number, because the mean of its divisors is an integer number (33325201).

Almost surely, 2^66650401 is an apocalyptic number.

It is an amenable number.

66650401 is a deficient number, since it is larger than the sum of its proper divisors (1).

66650401 is an equidigital number, since it uses as much as digits as its factorization.

66650401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 66650401 is about 8163.9696839222. The cubic root of 66650401 is about 405.4471533325.

The spelling of 66650401 in words is "sixty-six million, six hundred fifty thousand, four hundred one".