221855481 has 12 divisors (see below), whose sum is σ = 331508580. Its totient is φ = 142803360.

The previous prime is 221855407. The next prime is 221855483. The reversal of 221855481 is 184558122.

221855481 is a `hidden beast` number, since 2 + 21 + 8 + 554 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 138297600 + 83557881 = 11760^2 + 9141^2 .

It is not a de Polignac number, because 221855481 - 2¹¹ = 221853433 is a prime.

It is a super-2 number, since 2×221855481² = 98439708899482722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221855483) 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, 424750 + ... + 425271.

It is an arithmetic number, because the mean of its divisors is an integer number (27625715).

Almost surely, 2^221855481 is an apocalyptic number.

It is an amenable number.

221855481 is a deficient number, since it is larger than the sum of its proper divisors (109653099).

221855481 is a wasteful number, since it uses less digits than its factorization.

221855481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850056 (or 850053 counting only the distinct ones).

The product of its digits is 25600, while the sum is 36.

The square root of 221855481 is about 14894.8138961183. The cubic root of 221855481 is about 605.3734742947.

The spelling of 221855481 in words is "two hundred twenty-one million, eight hundred fifty-five thousand, four hundred eighty-one".