216056891 has 2 divisors, whose sum is σ = 216056892. Its totient is φ = 216056890.

The previous prime is 216056851. The next prime is 216056899. The reversal of 216056891 is 198650612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216056891 is a prime.

It is not a weakly prime, because it can be changed into another prime (216056899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108028445 + 108028446.

It is an arithmetic number, because the mean of its divisors is an integer number (108028446).

Almost surely, 2^216056891 is an apocalyptic number.

216056891 is a deficient number, since it is larger than the sum of its proper divisors (1).

216056891 is an equidigital number, since it uses as much as digits as its factorization.

216056891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 216056891 is about 14698.8738003971. The cubic root of 216056891 is about 600.0526722278.

The spelling of 216056891 in words is "two hundred sixteen million, fifty-six thousand, eight hundred ninety-one".