216749993 has 2 divisors, whose sum is σ = 216749994. Its totient is φ = 216749992.

The previous prime is 216749989. The next prime is 216750059. The reversal of 216749993 is 399947612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 129663769 + 87086224 = 11387^2 + 9332^2 .

It is a cyclic number.

It is not a de Polignac number, because 216749993 - 2² = 216749989 is a prime.

It is not a weakly prime, because it can be changed into another prime (216749963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108374996 + 108374997.

It is an arithmetic number, because the mean of its divisors is an integer number (108374997).

Almost surely, 2^216749993 is an apocalyptic number.

It is an amenable number.

216749993 is a deficient number, since it is larger than the sum of its proper divisors (1).

216749993 is an equidigital number, since it uses as much as digits as its factorization.

216749993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 734832, while the sum is 50.

The square root of 216749993 is about 14722.4316266030. The cubic root of 216749993 is about 600.6936357697.

The spelling of 216749993 in words is "two hundred sixteen million, seven hundred forty-nine thousand, nine hundred ninety-three".