99663821 has 2 divisors, whose sum is σ = 99663822. Its totient is φ = 99663820.

The previous prime is 99663737. The next prime is 99663833. The reversal of 99663821 is 12836699.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67059721 + 32604100 = 8189^2 + 5710^2 .

It is a cyclic number.

It is not a de Polignac number, because 99663821 - 2¹⁴ = 99647437 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99663841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49831910 + 49831911.

It is an arithmetic number, because the mean of its divisors is an integer number (49831911).

Almost surely, 2^99663821 is an apocalyptic number.

It is an amenable number.

99663821 is a deficient number, since it is larger than the sum of its proper divisors (1).

99663821 is an equidigital number, since it uses as much as digits as its factorization.

99663821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 44.

The square root of 99663821 is about 9983.1768991639. The cubic root of 99663821 is about 463.6381645113.

The spelling of 99663821 in words is "ninety-nine million, six hundred sixty-three thousand, eight hundred twenty-one".