221819 has 8 divisors (see below), whose sum is σ = 242592. Its totient is φ = 201600.

The previous prime is 221813. The next prime is 221827. The reversal of 221819 is 918122.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221819 is a prime.

It is a super-2 number, since 2×221819² = 98407337522, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 221794 and 221803.

It is not an unprimeable number, because it can be changed into a prime (221813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1394 + ... + 1544.

It is an arithmetic number, because the mean of its divisors is an integer number (30324).

2²²¹⁸¹⁹ is an apocalyptic number.

221819 is a deficient number, since it is larger than the sum of its proper divisors (20773).

221819 is a wasteful number, since it uses less digits than its factorization.

221819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277.

The product of its digits is 288, while the sum is 23.

The square root of 221819 is about 470.9766448562. The cubic root of 221819 is about 60.5340290770.

The spelling of 221819 in words is "two hundred twenty-one thousand, eight hundred nineteen".