666722281 has 2 divisors, whose sum is σ = 666722282. Its totient is φ = 666722280.

The previous prime is 666722219. The next prime is 666722297. The reversal of 666722281 is 182227666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 525326400 + 141395881 = 22920^2 + 11891^2 .

It is a cyclic number.

It is not a de Polignac number, because 666722281 - 2²⁹ = 129851369 is a prime.

It is a super-2 number, since 2×666722281² = 889037199963685922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (666722081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333361140 + 333361141.

It is an arithmetic number, because the mean of its divisors is an integer number (333361141).

Almost surely, 2^666722281 is an apocalyptic number.

It is an amenable number.

666722281 is a deficient number, since it is larger than the sum of its proper divisors (1).

666722281 is an equidigital number, since it uses as much as digits as its factorization.

666722281 is an odious number, because the sum of its binary digits is odd.

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

The square root of 666722281 is about 25820.9659191906. The cubic root of 666722281 is about 873.6047558584.

The spelling of 666722281 in words is "six hundred sixty-six million, seven hundred twenty-two thousand, two hundred eighty-one".