216863791 has 4 divisors (see below), whose sum is σ = 220100632. Its totient is φ = 213626952.

The previous prime is 216863789. The next prime is 216863797. The reversal of 216863791 is 197368612.

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 216863791 - 2¹ = 216863789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216863797) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1618320 + ... + 1618453.

It is an arithmetic number, because the mean of its divisors is an integer number (55025158).

Almost surely, 2^216863791 is an apocalyptic number.

216863791 is a deficient number, since it is larger than the sum of its proper divisors (3236841).

216863791 is an equidigital number, since it uses as much as digits as its factorization.

216863791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3236840.

The product of its digits is 108864, while the sum is 43.

The square root of 216863791 is about 14726.2959022288. The cubic root of 216863791 is about 600.7987426932.

The spelling of 216863791 in words is "two hundred sixteen million, eight hundred sixty-three thousand, seven hundred ninety-one".