216449856 has 126 divisors (see below), whose sum is σ = 721800690. Its totient is φ = 61834752.

The previous prime is 216449851. The next prime is 216449861. The reversal of 216449856 is 658944612.

It is an interprime number because it is at equal distance from previous prime (216449851) and next prime (216449861).

It can be written as a sum of positive squares in only one way, i.e., 213627456 + 2822400 = 14616^2 + 1680^2 .

It is a tau number, because it is divible by the number of its divisors (126).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216449851) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 24390 + ... + 32058.

Almost surely, 2^216449856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216449856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (360900345).

216449856 is an abundant number, since it is smaller than the sum of its proper divisors (505350834).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216449856 is a wasteful number, since it uses less digits than its factorization.

216449856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7701 (or 7681 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 216449856 is about 14712.2349084019. The cubic root of 216449856 is about 600.4162445007.

The spelling of 216449856 in words is "two hundred sixteen million, four hundred forty-nine thousand, eight hundred fifty-six".