216621393 has 8 divisors (see below), whose sum is σ = 291528288. Its totient is φ = 143064384.

The previous prime is 216621373. The next prime is 216621407. The reversal of 216621393 is 393126612.

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

It is not a de Polignac number, because 216621393 - 2²⁰ = 215572817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216621373) 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 in 7 ways as a sum of consecutive naturals, for example, 337096 + ... + 337737.

It is an arithmetic number, because the mean of its divisors is an integer number (36441036).

Almost surely, 2^216621393 is an apocalyptic number.

It is an amenable number.

216621393 is a deficient number, since it is larger than the sum of its proper divisors (74906895).

216621393 is a wasteful number, since it uses less digits than its factorization.

216621393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674943.

The product of its digits is 11664, while the sum is 33.

The square root of 216621393 is about 14718.0634935443. The cubic root of 216621393 is about 600.5748130297.

The spelling of 216621393 in words is "two hundred sixteen million, six hundred twenty-one thousand, three hundred ninety-three".