8261821 has 4 divisors (see below), whose sum is σ = 8284000. Its totient is φ = 8239644.

The previous prime is 8261819. The next prime is 8261833. The reversal of 8261821 is 1281628.

8261821 is digitally balanced in base 3, 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8261821 - 2¹ = 8261819 is a prime.

It is a Duffinian number.

8261821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 8261821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8261521) 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 in 3 ways as a sum of consecutive naturals, for example, 10521 + ... + 11278.

It is an arithmetic number, because the mean of its divisors is an integer number (2071000).

Almost surely, 2^8261821 is an apocalyptic number.

8261821 is the 1660-th hex number.

It is an amenable number.

8261821 is a deficient number, since it is larger than the sum of its proper divisors (22179).

8261821 is a wasteful number, since it uses less digits than its factorization.

8261821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22178.

The product of its digits is 1536, while the sum is 28.

The square root of 8261821 is about 2874.3383586488. The cubic root of 8261821 is about 202.1584630513.

The spelling of 8261821 in words is "eight million, two hundred sixty-one thousand, eight hundred twenty-one".