221739009 has 4 divisors (see below), whose sum is σ = 295652016. Its totient is φ = 147826004.

The previous prime is 221738981. The next prime is 221739013. The reversal of 221739009 is 900937122.

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 221739009 - 2⁵ = 221738977 is a prime.

It is a super-2 number, since 2×221739009² = 98336376224604162, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221739019) 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 in 3 ways as a sum of consecutive naturals, for example, 36956499 + ... + 36956504.

It is an arithmetic number, because the mean of its divisors is an integer number (73913004).

Almost surely, 2^221739009 is an apocalyptic number.

It is an amenable number.

221739009 is a deficient number, since it is larger than the sum of its proper divisors (73913007).

221739009 is an equidigital number, since it uses as much as digits as its factorization.

221739009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73913006.

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 221739009 is about 14890.9035656000. The cubic root of 221739009 is about 605.2675173275.

The spelling of 221739009 in words is "two hundred twenty-one million, seven hundred thirty-nine thousand, nine".