99966221 has 4 divisors (see below), whose sum is σ = 99993600. Its totient is φ = 99938844.

The previous prime is 99966203. The next prime is 99966233. The reversal of 99966221 is 12266999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 99966221 - 2⁶ = 99966157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99966281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7181 + ... + 15858.

It is an arithmetic number, because the mean of its divisors is an integer number (24998400).

Almost surely, 2^99966221 is an apocalyptic number.

It is an amenable number.

99966221 is a deficient number, since it is larger than the sum of its proper divisors (27379).

99966221 is a wasteful number, since it uses less digits than its factorization.

99966221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27378.

The product of its digits is 104976, while the sum is 44.

The square root of 99966221 is about 9998.3109073483. The cubic root of 99966221 is about 464.1066147325.

The spelling of 99966221 in words is "ninety-nine million, nine hundred sixty-six thousand, two hundred twenty-one".