216699869 has 4 divisors (see below), whose sum is σ = 216729600. Its totient is φ = 216670140.

The previous prime is 216699863. The next prime is 216699871. The reversal of 216699869 is 968996612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 216699869 - 2⁴ = 216699853 is a prime.

It is a super-2 number, since 2×216699869² = 93917666449234322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216699863) 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, 4334 + ... + 21264.

It is an arithmetic number, because the mean of its divisors is an integer number (54182400).

Almost surely, 2^216699869 is an apocalyptic number.

It is an amenable number.

216699869 is a deficient number, since it is larger than the sum of its proper divisors (29731).

216699869 is a wasteful number, since it uses less digits than its factorization.

216699869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29730.

The product of its digits is 2519424, while the sum is 56.

The square root of 216699869 is about 14720.7292278610. The cubic root of 216699869 is about 600.6473282110.

The spelling of 216699869 in words is "two hundred sixteen million, six hundred ninety-nine thousand, eight hundred sixty-nine".