99819661 has 2 divisors, whose sum is σ = 99819662. Its totient is φ = 99819660.

The previous prime is 99819637. The next prime is 99819677. The reversal of 99819661 is 16691899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90364036 + 9455625 = 9506^2 + 3075^2 .

It is a cyclic number.

It is not a de Polignac number, because 99819661 - 2¹³ = 99811469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99819611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49909830 + 49909831.

It is an arithmetic number, because the mean of its divisors is an integer number (49909831).

Almost surely, 2^99819661 is an apocalyptic number.

It is an amenable number.

99819661 is a deficient number, since it is larger than the sum of its proper divisors (1).

99819661 is an equidigital number, since it uses as much as digits as its factorization.

99819661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 49.

The square root of 99819661 is about 9990.9789810609. The cubic root of 99819661 is about 463.8796956363.

The spelling of 99819661 in words is "ninety-nine million, eight hundred nineteen thousand, six hundred sixty-one".