216538811 has 2 divisors, whose sum is σ = 216538812. Its totient is φ = 216538810.

The previous prime is 216538799. The next prime is 216538831. The reversal of 216538811 is 118835612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216538811 - 2⁶ = 216538747 is a prime.

It is not a weakly prime, because it can be changed into another prime (216538831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108269405 + 108269406.

It is an arithmetic number, because the mean of its divisors is an integer number (108269406).

Almost surely, 2^216538811 is an apocalyptic number.

216538811 is a deficient number, since it is larger than the sum of its proper divisors (1).

216538811 is an equidigital number, since it uses as much as digits as its factorization.

216538811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 35.

The square root of 216538811 is about 14715.2577619286. The cubic root of 216538811 is about 600.4984848142.

The spelling of 216538811 in words is "two hundred sixteen million, five hundred thirty-eight thousand, eight hundred eleven".