521838216 has 24 divisors (see below), whose sum is σ = 1413312030. Its totient is φ = 173946048.

The previous prime is 521838193. The next prime is 521838241. The reversal of 521838216 is 612838125.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 464230116 + 57608100 = 21546^2 + 7590^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3623805 + ... + 3623948.

Almost surely, 2^521838216 is an apocalyptic number.

It is an amenable number.

521838216 is an abundant number, since it is smaller than the sum of its proper divisors (891473814).

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

521838216 is a wasteful number, since it uses less digits than its factorization.

521838216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7247765 (or 7247758 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 521838216 is about 22843.7784965623. The cubic root of 521838216 is about 805.0915966398.

Subtracting 521838216 from its reverse (612838125), we obtain a palindrome (90999909).

It can be divided in two parts, 5218 and 38216, that added together give a palindrome (43434).

The spelling of 521838216 in words is "five hundred twenty-one million, eight hundred thirty-eight thousand, two hundred sixteen".