221388447 has 8 divisors (see below), whose sum is σ = 337353856. Its totient is φ = 126507672.

The previous prime is 221388421. The next prime is 221388449. The reversal of 221388447 is 744883122.

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

It is not a de Polignac number, because 221388447 - 2⁶ = 221388383 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221388449) 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, 5271133 + ... + 5271174.

It is an arithmetic number, because the mean of its divisors is an integer number (42169232).

Almost surely, 2^221388447 is an apocalyptic number.

221388447 is a deficient number, since it is larger than the sum of its proper divisors (115965409).

221388447 is a wasteful number, since it uses less digits than its factorization.

221388447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10542317.

The product of its digits is 86016, while the sum is 39.

The square root of 221388447 is about 14879.1278978306. The cubic root of 221388447 is about 604.9483798136.

The spelling of 221388447 in words is "two hundred twenty-one million, three hundred eighty-eight thousand, four hundred forty-seven".