99021691 has 2 divisors, whose sum is σ = 99021692. Its totient is φ = 99021690.

The previous prime is 99021679. The next prime is 99021697. The reversal of 99021691 is 19612099.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99021691 - 2¹⁹ = 98497403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99021691.

It is not a weakly prime, because it can be changed into another prime (99021697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49510845 + 49510846.

It is an arithmetic number, because the mean of its divisors is an integer number (49510846).

Almost surely, 2^99021691 is an apocalyptic number.

99021691 is a deficient number, since it is larger than the sum of its proper divisors (1).

99021691 is an equidigital number, since it uses as much as digits as its factorization.

99021691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 99021691 is about 9950.9643251295. The cubic root of 99021691 is about 462.6402843016.

The spelling of 99021691 in words is "ninety-nine million, twenty-one thousand, six hundred ninety-one".