216766191 has 32 divisors (see below), whose sum is σ = 308206080. Its totient is φ = 135235584.

The previous prime is 216766183. The next prime is 216766211. The reversal of 216766191 is 191667612.

It is not a de Polignac number, because 216766191 - 2³ = 216766183 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216766111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 930211 + ... + 930443.

It is an arithmetic number, because the mean of its divisors is an integer number (9631440).

Almost surely, 2^216766191 is an apocalyptic number.

216766191 is a deficient number, since it is larger than the sum of its proper divisors (91439889).

216766191 is a wasteful number, since it uses less digits than its factorization.

216766191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495.

The product of its digits is 27216, while the sum is 39.

The square root of 216766191 is about 14722.9817292558. The cubic root of 216766191 is about 600.7085989276.

The spelling of 216766191 in words is "two hundred sixteen million, seven hundred sixty-six thousand, one hundred ninety-one".