216949 has 4 divisors (see below), whose sum is σ = 224460. Its totient is φ = 209440.
The previous prime is 216947. The next prime is 216967. The reversal of 216949 is 949612.
It is a happy number.
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 154449 + 62500 = 393^2 + 250^2 .
It is a cyclic number.
It is not a de Polignac number, because 216949 - 21 = 216947 is a prime.
It is a super-3 number, since 3×2169493 = 30633330228355047, which contains 333 as substring.
It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is an alternating number because its digits alternate between even and odd.
It is a self number, because there is not a number n which added to its sum of digits gives 216949.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (216947) 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, 3712 + ... + 3769.
It is an arithmetic number, because the mean of its divisors is an integer number (56115).
2216949 is an apocalyptic number.
216949 is a gapful number since it is divisible by the number (29) formed by its first and last digit.
It is an amenable number.
216949 is a deficient number, since it is larger than the sum of its proper divisors (7511).
216949 is an equidigital number, since it uses as much as digits as its factorization.
216949 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 7510.
The product of its digits is 3888, while the sum is 31.
The square root of 216949 is about 465.7778440416. Note that the first 3 decimals coincide. The cubic root of 216949 is about 60.0877419969.
The spelling of 216949 in words is "two hundred sixteen thousand, nine hundred forty-nine".
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