8221691321 has 4 divisors (see below), whose sum is σ = 8223351552. Its totient is φ = 8220031092.

The previous prime is 8221691311. The next prime is 8221691323. The reversal of 8221691321 is 1231961228.

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 a de Polignac number, because none of the positive numbers 2^k-8221691321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8221691323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 822665 + ... + 832598.

It is an arithmetic number, because the mean of its divisors is an integer number (2055837888).

Almost surely, 2^8221691321 is an apocalyptic number.

It is an amenable number.

8221691321 is a deficient number, since it is larger than the sum of its proper divisors (1660231).

8221691321 is a wasteful number, since it uses less digits than its factorization.

8221691321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1660230.

The product of its digits is 10368, while the sum is 35.

The square root of 8221691321 is about 90673.5425634181. The cubic root of 8221691321 is about 2018.3062069171.

The spelling of 8221691321 in words is "eight billion, two hundred twenty-one million, six hundred ninety-one thousand, three hundred twenty-one".