66628417 has 2 divisors, whose sum is σ = 66628418. Its totient is φ = 66628416.

The previous prime is 66628381. The next prime is 66628433. The reversal of 66628417 is 71482666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46566976 + 20061441 = 6824^2 + 4479^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66628417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66628417.

It is not a weakly prime, because it can be changed into another prime (66608417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33314208 + 33314209.

It is an arithmetic number, because the mean of its divisors is an integer number (33314209).

Almost surely, 2^66628417 is an apocalyptic number.

It is an amenable number.

66628417 is a deficient number, since it is larger than the sum of its proper divisors (1).

66628417 is an equidigital number, since it uses as much as digits as its factorization.

66628417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 40.

The square root of 66628417 is about 8162.6231690554. The cubic root of 66628417 is about 405.4025708030.

The spelling of 66628417 in words is "sixty-six million, six hundred twenty-eight thousand, four hundred seventeen".