820736281 has 4 divisors (see below), whose sum is σ = 821411892. Its totient is φ = 820060672.

The previous prime is 820736269. The next prime is 820736291. The reversal of 820736281 is 182637028.

820736281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 490223881 + 330512400 = 22141^2 + 18180^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820736281 is a prime.

It is a super-2 number, since 2×820736281² = 1347216085899421922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 820736281.

It is not an unprimeable number, because it can be changed into a prime (820736291) 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, 335980 + ... + 338413.

It is an arithmetic number, because the mean of its divisors is an integer number (205352973).

Almost surely, 2^820736281 is an apocalyptic number.

It is an amenable number.

820736281 is a deficient number, since it is larger than the sum of its proper divisors (675611).

820736281 is a wasteful number, since it uses less digits than its factorization.

820736281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675610.

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 820736281 is about 28648.4952658949. The cubic root of 820736281 is about 936.2702215058.

The spelling of 820736281 in words is "eight hundred twenty million, seven hundred thirty-six thousand, two hundred eighty-one".