8219861 has 4 divisors (see below), whose sum is σ = 8852172. Its totient is φ = 7587552.

The previous prime is 8219851. The next prime is 8219879. The reversal of 8219861 is 1689128.

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 2579236 + 5640625 = 1606^2 + 2375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8219861 is a prime.

It is a super-2 number, since 2×8219861² = 135132229718642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8219851) 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, 316136 + ... + 316161.

It is an arithmetic number, because the mean of its divisors is an integer number (2213043).

Almost surely, 2^8219861 is an apocalyptic number.

It is an amenable number.

8219861 is a deficient number, since it is larger than the sum of its proper divisors (632311).

8219861 is a wasteful number, since it uses less digits than its factorization.

8219861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632310.

The product of its digits is 6912, while the sum is 35.

The square root of 8219861 is about 2867.0299963551. The cubic root of 8219861 is about 201.8156423365.

The spelling of 8219861 in words is "eight million, two hundred nineteen thousand, eight hundred sixty-one".