216749747 has 4 divisors (see below), whose sum is σ = 217014576. Its totient is φ = 216484920.

The previous prime is 216749717. The next prime is 216749749. The reversal of 216749747 is 747947612.

It is a happy number.

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 216749747 - 2¹⁸ = 216487603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216749749) 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 in 3 ways as a sum of consecutive naturals, for example, 131183 + ... + 132824.

It is an arithmetic number, because the mean of its divisors is an integer number (54253644).

Almost surely, 2^216749747 is an apocalyptic number.

216749747 is a deficient number, since it is larger than the sum of its proper divisors (264829).

216749747 is an equidigital number, since it uses as much as digits as its factorization.

216749747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264828.

The product of its digits is 592704, while the sum is 47.

The square root of 216749747 is about 14722.4232720025. The cubic root of 216749747 is about 600.6934085175.

The spelling of 216749747 in words is "two hundred sixteen million, seven hundred forty-nine thousand, seven hundred forty-seven".