221320520 has 16 divisors (see below), whose sum is σ = 497971260. Its totient is φ = 88528192.

The previous prime is 221320511. The next prime is 221320523. The reversal of 221320520 is 25023122.

It can be written as a sum of positive squares in 2 ways, for example, as 207763396 + 13557124 = 14414^2 + 3682^2 .

It is not an unprimeable number, because it can be changed into a prime (221320523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2766467 + ... + 2766546.

Almost surely, 2^221320520 is an apocalyptic number.

221320520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221320520 is an abundant number, since it is smaller than the sum of its proper divisors (276650740).

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

221320520 is a wasteful number, since it uses less digits than its factorization.

221320520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5533024 (or 5533020 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 221320520 is about 14876.8450956512. The cubic root of 221320520 is about 604.8865028540.

Adding to 221320520 its reverse (25023122), we get a palindrome (246343642).

The spelling of 221320520 in words is "two hundred twenty-one million, three hundred twenty thousand, five hundred twenty".