66428777 has 2 divisors, whose sum is σ = 66428778. Its totient is φ = 66428776.

The previous prime is 66428773. The next prime is 66428779. The reversal of 66428777 is 77782466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56310016 + 10118761 = 7504^2 + 3181^2 .

It is a cyclic number.

It is not a de Polignac number, because 66428777 - 2² = 66428773 is a prime.

Together with 66428779, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66428771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33214388 + 33214389.

It is an arithmetic number, because the mean of its divisors is an integer number (33214389).

Almost surely, 2^66428777 is an apocalyptic number.

It is an amenable number.

66428777 is a deficient number, since it is larger than the sum of its proper divisors (1).

66428777 is an equidigital number, since it uses as much as digits as its factorization.

66428777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 790272, while the sum is 47.

The square root of 66428777 is about 8150.3850829271. The cubic root of 66428777 is about 404.9972605617.

It can be divided in two parts, 66 and 428777, that multiplied together give a palindrome (28299282).

The spelling of 66428777 in words is "sixty-six million, four hundred twenty-eight thousand, seven hundred seventy-seven".