221648818 has 4 divisors (see below), whose sum is σ = 332473230. Its totient is φ = 110824408.

The previous prime is 221648753. The next prime is 221648821. The reversal of 221648818 is 818846122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 131721529 + 89927289 = 11477^2 + 9483^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55412203 + ... + 55412206.

Almost surely, 2^221648818 is an apocalyptic number.

221648818 is a deficient number, since it is larger than the sum of its proper divisors (110824412).

221648818 is a wasteful number, since it uses less digits than its factorization.

221648818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110824411.

The product of its digits is 49152, while the sum is 40.

The square root of 221648818 is about 14887.8748651377. The cubic root of 221648818 is about 605.1854432322.

The spelling of 221648818 in words is "two hundred twenty-one million, six hundred forty-eight thousand, eight hundred eighteen".