820291 has 8 divisors (see below), whose sum is σ = 866304. Its totient is φ = 775560.

The previous prime is 820279. The next prime is 820319. The reversal of 820291 is 192028.

820291 = T₇₃₈ + T₇₃₉ + T₇₄₀.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 820291 - 2⁷ = 820163 is a prime.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (820201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1176 + ... + 1738.

It is an arithmetic number, because the mean of its divisors is an integer number (108288).

2⁸²⁰²⁹¹ is an apocalyptic number.

820291 is the 740-th centered triangular number.

820291 is a deficient number, since it is larger than the sum of its proper divisors (46013).

820291 is a wasteful number, since it uses less digits than its factorization.

820291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 820291 is about 905.6991774314. The cubic root of 820291 is about 93.6100870007.

It can be divided in two parts, 820 and 291, that added together give a palindrome (1111).

The spelling of 820291 in words is "eight hundred twenty thousand, two hundred ninety-one".