215217 has 10 divisors (see below), whose sum is σ = 321618. Its totient is φ = 143424.

The previous prime is 215197. The next prime is 215239. The reversal of 215217 is 712512.

It can be written as a sum of positive squares in only one way, i.e., 194481 + 20736 = 441^2 + 144^2 .

It is not a de Polignac number, because 215217 - 2⁶ = 215153 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 215217.

It is not an unprimeable number, because it can be changed into a prime (215297) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1248 + ... + 1409.

2²¹⁵²¹⁷ is an apocalyptic number.

215217 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

215217 is a deficient number, since it is larger than the sum of its proper divisors (106401).

215217 is an equidigital number, since it uses as much as digits as its factorization.

215217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2669 (or 2660 counting only the distinct ones).

The product of its digits is 140, while the sum is 18.

The square root of 215217 is about 463.9148628790. The cubic root of 215217 is about 59.9274122190.

Adding to 215217 its reverse (712512), we get a palindrome (927729).

It can be divided in two parts, 21521 and 7, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 215217 in words is "two hundred fifteen thousand, two hundred seventeen".