221644399 has 8 divisors (see below), whose sum is σ = 233573472. Its totient is φ = 209906400.

The previous prime is 221644387. The next prime is 221644417. The reversal of 221644399 is 993446122.

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 221644399 - 2¹⁵ = 221611631 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 (221644309) 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, 45384 + ... + 50029.

It is an arithmetic number, because the mean of its divisors is an integer number (29196684).

Almost surely, 2^221644399 is an apocalyptic number.

221644399 is a deficient number, since it is larger than the sum of its proper divisors (11929073).

221644399 is a wasteful number, since it uses less digits than its factorization.

221644399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95537.

The product of its digits is 93312, while the sum is 40.

The square root of 221644399 is about 14887.7264550367. The cubic root of 221644399 is about 605.1814213561.

The spelling of 221644399 in words is "two hundred twenty-one million, six hundred forty-four thousand, three hundred ninety-nine".