8223991 has 2 divisors, whose sum is σ = 8223992. Its totient is φ = 8223990.

The previous prime is 8223989. The next prime is 8223997. The reversal of 8223991 is 1993228.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8223991 - 2¹ = 8223989 is a prime.

Together with 8223989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8223997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4111995 + 4111996.

It is an arithmetic number, because the mean of its divisors is an integer number (4111996).

Almost surely, 2^8223991 is an apocalyptic number.

8223991 is a deficient number, since it is larger than the sum of its proper divisors (1).

8223991 is an equidigital number, since it uses as much as digits as its factorization.

8223991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 34.

The square root of 8223991 is about 2867.7501634557. The cubic root of 8223991 is about 201.8494368677.

The spelling of 8223991 in words is "eight million, two hundred twenty-three thousand, nine hundred ninety-one".