221744813 has 8 divisors (see below), whose sum is σ = 224349048. Its totient is φ = 219147264.

The previous prime is 221744797. The next prime is 221744819. The reversal of 221744813 is 318447122.

It can be written as a sum of positive squares in 4 ways, for example, as 160326244 + 61418569 = 12662^2 + 7837^2 .

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 221744813 - 2⁴ = 221744797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221744813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221744819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 99095 + ... + 101307.

It is an arithmetic number, because the mean of its divisors is an integer number (28043631).

Almost surely, 2^221744813 is an apocalyptic number.

It is an amenable number.

221744813 is a deficient number, since it is larger than the sum of its proper divisors (2604235).

221744813 is a wasteful number, since it uses less digits than its factorization.

221744813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3343.

The product of its digits is 10752, while the sum is 32.

The square root of 221744813 is about 14891.0984484020. The cubic root of 221744813 is about 605.2727982237.

The spelling of 221744813 in words is "two hundred twenty-one million, seven hundred forty-four thousand, eight hundred thirteen".