216997393 has 8 divisors (see below), whose sum is σ = 223465088. Its totient is φ = 210594384.

The previous prime is 216997373. The next prime is 216997399. The reversal of 216997393 is 393799612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216997393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216997399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9321 + ... + 22822.

It is an arithmetic number, because the mean of its divisors is an integer number (27933136).

Almost surely, 2^216997393 is an apocalyptic number.

It is an amenable number.

216997393 is a deficient number, since it is larger than the sum of its proper divisors (6467695).

216997393 is a wasteful number, since it uses less digits than its factorization.

216997393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32343.

The product of its digits is 551124, while the sum is 49.

The square root of 216997393 is about 14730.8313750447. The cubic root of 216997393 is about 600.9220942149.

It can be divided in two parts, 21699 and 7393, that added together give a palindrome (29092).

The spelling of 216997393 in words is "two hundred sixteen million, nine hundred ninety-seven thousand, three hundred ninety-three".