646990273 has 2 divisors, whose sum is σ = 646990274. Its totient is φ = 646990272.

The previous prime is 646990187. The next prime is 646990303. The reversal of 646990273 is 372099646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 420578064 + 226412209 = 20508^2 + 15047^2 .

It is a cyclic number.

It is not a de Polignac number, because 646990273 - 2¹⁷ = 646859201 is a prime.

It is a super-2 number, since 2×646990273² = 837192826713229058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (646990073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323495136 + 323495137.

It is an arithmetic number, because the mean of its divisors is an integer number (323495137).

Almost surely, 2^646990273 is an apocalyptic number.

It is an amenable number.

646990273 is a deficient number, since it is larger than the sum of its proper divisors (1).

646990273 is an equidigital number, since it uses as much as digits as its factorization.

646990273 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 489888, while the sum is 46.

The square root of 646990273 is about 25436.0034793204. The cubic root of 646990273 is about 864.9000399041.

The spelling of 646990273 in words is "six hundred forty-six million, nine hundred ninety thousand, two hundred seventy-three".