219961 has 9 divisors (see below), whose sum is σ = 259749.
Its totient is φ = 185724.
The previous prime is 219959. The next prime is 219971. The reversal of 219961 is 169912.
219961 = T468 + T469.
The square root of 219961 is 469.
It is a perfect power (a square), and thus also a powerful number.
It is not a de Polignac number, because 219961 - 21 = 219959 is a prime.
It is not an unprimeable number, because it can be changed into a prime (219911) 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 8 ways as a sum of consecutive naturals, for example, 3250 + ... + 3316.
It is an arithmetic number, because the mean of its divisors is an integer number (28861).
219961 is a Friedman number, since it can be written as (9*(61-9)+1)^2, using all its digits and the basic arithmetic operations.
2219961 is an apocalyptic number.
219961 is the 469-th square number.
219961 is the 235-th centered octagonal number.
It is an amenable number.
219961 is a deficient number, since it is larger than the sum of its proper divisors (39788).
219961 is an frugal number, since it uses more digits than its factorization.
219961 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 148 (or 74 counting only the distinct ones).
The product of its digits is 972, while the sum is 28.
The cubic root of 219961 is about 60.3645399508.
The spelling of 219961 in words is "two hundred nineteen thousand, nine hundred sixty-one".