216705215 has 4 divisors (see below), whose sum is σ = 260046264. Its totient is φ = 173364168.

The previous prime is 216705199. The next prime is 216705217. The reversal of 216705215 is 512507612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216705215 - 2⁴ = 216705199 is a prime.

It is a super-2 number, since 2×216705215² = 93922300416392450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216705217) 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 3 ways as a sum of consecutive naturals, for example, 21670517 + ... + 21670526.

It is an arithmetic number, because the mean of its divisors is an integer number (65011566).

Almost surely, 2^216705215 is an apocalyptic number.

216705215 is a deficient number, since it is larger than the sum of its proper divisors (43341049).

216705215 is an equidigital number, since it uses as much as digits as its factorization.

216705215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43341048.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 216705215 is about 14720.9108074195. The cubic root of 216705215 is about 600.6522675067.

The spelling of 216705215 in words is "two hundred sixteen million, seven hundred five thousand, two hundred fifteen".