205521216 has 28 divisors (see below), whose sum is σ = 543775392. Its totient is φ = 68507008.

The previous prime is 205521193. The next prime is 205521221. The reversal of 205521216 is 612125502.

It is a happy number.

It is a super-2 number, since 2×205521216² = 84477940452237312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 535020 + ... + 535403.

Almost surely, 2^205521216 is an apocalyptic number.

It is an amenable number.

205521216 is an abundant number, since it is smaller than the sum of its proper divisors (338254176).

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

205521216 is a wasteful number, since it uses less digits than its factorization.

205521216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070438 (or 1070428 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 205521216 is about 14336.0111607099. The cubic root of 205521216 is about 590.1361516676.

Adding to 205521216 its reverse (612125502), we get a palindrome (817646718).

The spelling of 205521216 in words is "two hundred five million, five hundred twenty-one thousand, two hundred sixteen".