665622281 has 2 divisors, whose sum is σ = 665622282. Its totient is φ = 665622280.

The previous prime is 665622271. The next prime is 665622289. The reversal of 665622281 is 182226566.

665622281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 602260681 + 63361600 = 24541^2 + 7960^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665622281 is a prime.

It is a super-2 number, since 2×665622281² = 886106041927285922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (665622289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332811140 + 332811141.

It is an arithmetic number, because the mean of its divisors is an integer number (332811141).

Almost surely, 2^665622281 is an apocalyptic number.

It is an amenable number.

665622281 is a deficient number, since it is larger than the sum of its proper divisors (1).

665622281 is an equidigital number, since it uses as much as digits as its factorization.

665622281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 38.

The square root of 665622281 is about 25799.6566062419. The cubic root of 665622281 is about 873.1240488581.

The spelling of 665622281 in words is "six hundred sixty-five million, six hundred twenty-two thousand, two hundred eighty-one".