216820225 has 12 divisors (see below), whose sum is σ = 269310640. Its totient is φ = 173163600.

The previous prime is 216820223. The next prime is 216820237. The reversal of 216820225 is 522028612.

It is not a de Polignac number, because 216820225 - 2¹ = 216820223 is a prime.

It is a super-2 number, since 2×216820225² = 94022019938101250, which contains 22 as substring.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 216820193 and 216820202.

It is not an unprimeable number, because it can be changed into a prime (216820223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8470 + ... + 22480.

Almost surely, 2^216820225 is an apocalyptic number.

216820225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

216820225 is a deficient number, since it is larger than the sum of its proper divisors (52490415).

216820225 is a wasteful number, since it uses less digits than its factorization.

216820225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14640 (or 14635 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 216820225 is about 14724.8166372285. The cubic root of 216820225 is about 600.7585082971.

Adding to 216820225 its reverse (522028612), we get a palindrome (738848837).

The spelling of 216820225 in words is "two hundred sixteen million, eight hundred twenty thousand, two hundred twenty-five".