221821049 has 4 divisors (see below), whose sum is σ = 234869364. Its totient is φ = 208772736.

The previous prime is 221821013. The next prime is 221821051. The reversal of 221821049 is 940128122.

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

It can be written as a sum of positive squares in 2 ways, for example, as 170955625 + 50865424 = 13075^2 + 7132^2 .

It is a cyclic number.

It is not a de Polignac number, because 221821049 - 2¹² = 221816953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221821009) 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, 6524132 + ... + 6524165.

It is an arithmetic number, because the mean of its divisors is an integer number (58717341).

Almost surely, 2^221821049 is an apocalyptic number.

It is an amenable number.

221821049 is a deficient number, since it is larger than the sum of its proper divisors (13048315).

221821049 is a wasteful number, since it uses less digits than its factorization.

221821049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13048314.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 221821049 is about 14893.6580127247. The cubic root of 221821049 is about 605.3421546600.

The spelling of 221821049 in words is "two hundred twenty-one million, eight hundred twenty-one thousand, forty-nine".