8221531 has 4 divisors (see below), whose sum is σ = 8231112. Its totient is φ = 8211952.

The previous prime is 8221513. The next prime is 8221537. The reversal of 8221531 is 1351228.

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

It is a cyclic number.

It is not a de Polignac number, because 8221531 - 2⁷ = 8221403 is a prime.

It is a super-2 number, since 2×8221531² = 135187143967922, 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 (8221537) 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, 3361 + ... + 5266.

It is an arithmetic number, because the mean of its divisors is an integer number (2057778).

Almost surely, 2^8221531 is an apocalyptic number.

8221531 is a deficient number, since it is larger than the sum of its proper divisors (9581).

8221531 is an equidigital number, since it uses as much as digits as its factorization.

8221531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9580.

The product of its digits is 480, while the sum is 22.

The square root of 8221531 is about 2867.3212237208. The cubic root of 8221531 is about 201.8293088004.

Adding to 8221531 its reverse (1351228), we get a palindrome (9572759).

The spelling of 8221531 in words is "eight million, two hundred twenty-one thousand, five hundred thirty-one".