216861773 has 4 divisors (see below), whose sum is σ = 222722940. Its totient is φ = 211000608.

The previous prime is 216861719. The next prime is 216861787. The reversal of 216861773 is 377168612.

216861773 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 77668969 + 139192804 = 8813^2 + 11798^2 .

It is a cyclic number.

It is not a de Polignac number, because 216861773 - 2¹⁴ = 216845389 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 216861773.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216864773) 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, 2930528 + ... + 2930601.

It is an arithmetic number, because the mean of its divisors is an integer number (55680735).

Almost surely, 2^216861773 is an apocalyptic number.

It is an amenable number.

216861773 is a deficient number, since it is larger than the sum of its proper divisors (5861167).

216861773 is an equidigital number, since it uses as much as digits as its factorization.

216861773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5861166.

The product of its digits is 84672, while the sum is 41.

The square root of 216861773 is about 14726.2273851791. The cubic root of 216861773 is about 600.7968791338.

The spelling of 216861773 in words is "two hundred sixteen million, eight hundred sixty-one thousand, seven hundred seventy-three".