647281 has 4 divisors (see below), whose sum is σ = 654052. Its totient is φ = 640512.

The previous prime is 647263. The next prime is 647293. The reversal of 647281 is 182746.

647281 is nontrivially palindromic in base 9.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182746 = 2 ⋅91373.

It can be written as a sum of positive squares in 2 ways, for example, as 128881 + 518400 = 359^2 + 720^2 .

It is a cyclic number.

It is not a de Polignac number, because 647281 - 2¹¹ = 645233 is a prime.

It is a super-2 number, since 2×647281² = 837945385922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3240 + ... + 3433.

It is an arithmetic number, because the mean of its divisors is an integer number (163513).

2⁶⁴⁷²⁸¹ is an apocalyptic number.

647281 is the 465-th hex number.

It is an amenable number.

647281 is a deficient number, since it is larger than the sum of its proper divisors (6771).

647281 is an equidigital number, since it uses as much as digits as its factorization.

647281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6770.

The product of its digits is 2688, while the sum is 28.

The square root of 647281 is about 804.5377554845. The cubic root of 647281 is about 86.5029568972.

The spelling of 647281 in words is "six hundred forty-seven thousand, two hundred eighty-one".