66005021 has 2 divisors, whose sum is σ = 66005022. Its totient is φ = 66005020.

The previous prime is 66004987. The next prime is 66005029. The reversal of 66005021 is 12050066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43099225 + 22905796 = 6565^2 + 4786^2 .

It is a cyclic number.

It is not a de Polignac number, because 66005021 - 2²² = 61810717 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66004984 and 66005002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66005029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33002510 + 33002511.

It is an arithmetic number, because the mean of its divisors is an integer number (33002511).

Almost surely, 2^66005021 is an apocalyptic number.

It is an amenable number.

66005021 is a deficient number, since it is larger than the sum of its proper divisors (1).

66005021 is an equidigital number, since it uses as much as digits as its factorization.

66005021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 66005021 is about 8124.3474199470. The cubic root of 66005021 is about 404.1342498156.

Adding to 66005021 its reverse (12050066), we get a palindrome (78055087).

The spelling of 66005021 in words is "sixty-six million, five thousand, twenty-one".