8220421 has 8 divisors (see below), whose sum is σ = 9115488. Its totient is φ = 7350000.

The previous prime is 8220419. The next prime is 8220461. The reversal of 8220421 is 1240228.

8220421 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is the 1171-st star number.

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 8220421 - 2¹ = 8220419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8220461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5455 + ... + 6796.

It is an arithmetic number, because the mean of its divisors is an integer number (1139436).

Almost surely, 2^8220421 is an apocalyptic number.

It is an amenable number.

8220421 is a deficient number, since it is larger than the sum of its proper divisors (895067).

8220421 is a wasteful number, since it uses less digits than its factorization.

8220421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12323.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 8220421 is about 2867.1276567324. The cubic root of 8220421 is about 201.8202253091.

Adding to 8220421 its reverse (1240228), we get a palindrome (9460649).

It can be divided in two parts, 82 and 20421, that added together give a triangular number (20503 = T₂₀₂).

The spelling of 8220421 in words is "eight million, two hundred twenty thousand, four hundred twenty-one".