216894381 has 16 divisors (see below), whose sum is σ = 334041408. Its totient is φ = 123718400.

The previous prime is 216894361. The next prime is 216894397. The reversal of 216894381 is 183498612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216894381 is a prime.

It is a super-2 number, since 2×216894381² = 94086345018746322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216894311) 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 15 ways as a sum of consecutive naturals, for example, 192750 + ... + 193871.

It is an arithmetic number, because the mean of its divisors is an integer number (20877588).

Almost surely, 2^216894381 is an apocalyptic number.

It is an amenable number.

216894381 is a deficient number, since it is larger than the sum of its proper divisors (117147027).

216894381 is a wasteful number, since it uses less digits than its factorization.

216894381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386652.

The product of its digits is 82944, while the sum is 42.

The square root of 216894381 is about 14727.3344838773. The cubic root of 216894381 is about 600.8269901773.

The spelling of 216894381 in words is "two hundred sixteen million, eight hundred ninety-four thousand, three hundred eighty-one".