216485381 has 6 divisors (see below), whose sum is σ = 251829990. Its totient is φ = 185558856.

The previous prime is 216485363. The next prime is 216485383. The reversal of 216485381 is 183584612.

216485381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 213422881 + 3062500 = 14609^2 + 1750^2 .

It is not a de Polignac number, because 216485381 - 2⁶ = 216485317 is a prime.

It is a super-2 number, since 2×216485381² = 93731840373430322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216485383) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2208986 + ... + 2209083.

It is an arithmetic number, because the mean of its divisors is an integer number (41971665).

Almost surely, 2^216485381 is an apocalyptic number.

It is an amenable number.

216485381 is a deficient number, since it is larger than the sum of its proper divisors (35344609).

216485381 is an equidigital number, since it uses as much as digits as its factorization.

216485381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4418083 (or 4418076 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 216485381 is about 14713.4421873333. The cubic root of 216485381 is about 600.4490906307.

The spelling of 216485381 in words is "two hundred sixteen million, four hundred eighty-five thousand, three hundred eighty-one".