221728907329 has 4 divisors (see below), whose sum is σ = 233398849840. Its totient is φ = 210058964820.

The previous prime is 221728907303. The next prime is 221728907357. The reversal of 221728907329 is 923709827122.

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 221728907329 - 2⁵ = 221728907297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221728907129) 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, 5834971227 + ... + 5834971264.

It is an arithmetic number, because the mean of its divisors is an integer number (58349712460).

Almost surely, 2^221728907329 is an apocalyptic number.

It is an amenable number.

221728907329 is a deficient number, since it is larger than the sum of its proper divisors (11669942511).

221728907329 is a wasteful number, since it uses less digits than its factorization.

221728907329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11669942510.

The product of its (nonzero) digits is 1524096, while the sum is 52.

The spelling of 221728907329 in words is "two hundred twenty-one billion, seven hundred twenty-eight million, nine hundred seven thousand, three hundred twenty-nine".