221665816129 has 8 divisors (see below), whose sum is σ = 227197854720. Its totient is φ = 216192944016.

The previous prime is 221665816121. The next prime is 221665816133. The reversal of 221665816129 is 921618566122.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221665816129 - 2³ = 221665816121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221665816121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14784034 + ... + 14799019.

It is an arithmetic number, because the mean of its divisors is an integer number (28399731840).

Almost surely, 2^221665816129 is an apocalyptic number.

It is an amenable number.

221665816129 is a deficient number, since it is larger than the sum of its proper divisors (5532038591).

221665816129 is a wasteful number, since it uses less digits than its factorization.

221665816129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29583239.

The product of its digits is 622080, while the sum is 49.

The spelling of 221665816129 in words is "two hundred twenty-one billion, six hundred sixty-five million, eight hundred sixteen thousand, one hundred twenty-nine".