216649789 has 4 divisors (see below), whose sum is σ = 216808956. Its totient is φ = 216490624.

The previous prime is 216649787. The next prime is 216649841. The reversal of 216649789 is 987946612.

It is a happy number.

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 176225625 + 40424164 = 13275^2 + 6358^2 .

It is a cyclic number.

It is not a de Polignac number, because 216649789 - 2¹ = 216649787 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 (216649787) 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, 77524 + ... + 80269.

It is an arithmetic number, because the mean of its divisors is an integer number (54202239).

Almost surely, 2^216649789 is an apocalyptic number.

It is an amenable number.

216649789 is a deficient number, since it is larger than the sum of its proper divisors (159167).

216649789 is a wasteful number, since it uses less digits than its factorization.

216649789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159166.

The product of its digits is 1306368, while the sum is 52.

The square root of 216649789 is about 14719.0281268839. The cubic root of 216649789 is about 600.6010541702.

The spelling of 216649789 in words is "two hundred sixteen million, six hundred forty-nine thousand, seven hundred eighty-nine".