646106281 has 2 divisors, whose sum is σ = 646106282. Its totient is φ = 646106280.

The previous prime is 646106243. The next prime is 646106303. The reversal of 646106281 is 182601646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 645973056 + 133225 = 25416^2 + 365^2 .

It is a cyclic number.

It is not a de Polignac number, because 646106281 - 2¹¹ = 646104233 is a prime.

It is a super-2 number, since 2×646106281² = 834906652695301922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (646106221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323053140 + 323053141.

It is an arithmetic number, because the mean of its divisors is an integer number (323053141).

Almost surely, 2^646106281 is an apocalyptic number.

It is an amenable number.

646106281 is a deficient number, since it is larger than the sum of its proper divisors (1).

646106281 is an equidigital number, since it uses as much as digits as its factorization.

646106281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 646106281 is about 25418.6207532982. The cubic root of 646106281 is about 864.5059519636.

The spelling of 646106281 in words is "six hundred forty-six million, one hundred six thousand, two hundred eighty-one".