216851 has 2 divisors, whose sum is σ = 216852. Its totient is φ = 216850.

The previous prime is 216841. The next prime is 216859. The reversal of 216851 is 158612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 216851 - 2⁶ = 216787 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (216859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108425 + 108426.

It is an arithmetic number, because the mean of its divisors is an integer number (108426).

2²¹⁶⁸⁵¹ is an apocalyptic number.

216851 is a deficient number, since it is larger than the sum of its proper divisors (1).

216851 is an equidigital number, since it uses as much as digits as its factorization.

216851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 480, while the sum is 23.

The square root of 216851 is about 465.6726317919. The cubic root of 216851 is about 60.0786930413.

The spelling of 216851 in words is "two hundred sixteen thousand, eight hundred fifty-one".