99997716221 has 4 divisors (see below), whose sum is σ = 107689848252. Its totient is φ = 92305584192.

The previous prime is 99997716191. The next prime is 99997716233. The reversal of 99997716221 is 12261779999.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11082825625 + 88914890596 = 105275^2 + 298186^2 .

It is a cyclic number.

It is not a de Polignac number, because 99997716221 - 2⁶ = 99997716157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99997716121) 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 in 3 ways as a sum of consecutive naturals, for example, 3846065996 + ... + 3846066021.

It is an arithmetic number, because the mean of its divisors is an integer number (26922462063).

Almost surely, 2^99997716221 is an apocalyptic number.

It is an amenable number.

99997716221 is a deficient number, since it is larger than the sum of its proper divisors (7692132031).

99997716221 is a wasteful number, since it uses less digits than its factorization.

99997716221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7692132030.

The product of its digits is 7715736, while the sum is 62.

The spelling of 99997716221 in words is "ninety-nine billion, nine hundred ninety-seven million, seven hundred sixteen thousand, two hundred twenty-one".