8168591021 has 2 divisors, whose sum is σ = 8168591022. Its totient is φ = 8168591020.

The previous prime is 8168590999. The next prime is 8168591029. The reversal of 8168591021 is 1201958618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5576355625 + 2592235396 = 74675^2 + 50914^2 .

It is a cyclic number.

It is not a de Polignac number, because 8168591021 - 2²² = 8164396717 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8168591021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8168591029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4084295510 + 4084295511.

It is an arithmetic number, because the mean of its divisors is an integer number (4084295511).

Almost surely, 2^8168591021 is an apocalyptic number.

It is an amenable number.

8168591021 is a deficient number, since it is larger than the sum of its proper divisors (1).

8168591021 is an equidigital number, since it uses as much as digits as its factorization.

8168591021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 41.

The square root of 8168591021 is about 90380.2579162065. The cubic root of 8168591021 is about 2013.9517004689.

The spelling of 8168591021 in words is "eight billion, one hundred sixty-eight million, five hundred ninety-one thousand, twenty-one".