216740917 has 4 divisors (see below), whose sum is σ = 216797260. Its totient is φ = 216684576.

The previous prime is 216740861. The next prime is 216740921. The reversal of 216740917 is 719047612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1267876 + 215473041 = 1126^2 + 14679^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216740917 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 (216740947) 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, 21942 + ... + 30247.

It is an arithmetic number, because the mean of its divisors is an integer number (54199315).

Almost surely, 2^216740917 is an apocalyptic number.

It is an amenable number.

216740917 is a deficient number, since it is larger than the sum of its proper divisors (56343).

216740917 is an equidigital number, since it uses as much as digits as its factorization.

216740917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56342.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 216740917 is about 14722.1233862510. The cubic root of 216740917 is about 600.6852513456.

The spelling of 216740917 in words is "two hundred sixteen million, seven hundred forty thousand, nine hundred seventeen".