221481 has 16 divisors (see below), whose sum is σ = 353920. Its totient is φ = 136080.

The previous prime is 221477. The next prime is 221489. The reversal of 221481 is 184122.

It is not a de Polignac number, because 221481 - 2² = 221477 is a prime.

It is a super-2 number, since 2×221481² = 98107666722, which contains 22 as substring.

It is a Duffinian number.

221481 is a modest number, since divided by 481 gives 221 as remainder.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221489) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36 + ... + 666.

It is an arithmetic number, because the mean of its divisors is an integer number (22120).

2²²¹⁴⁸¹ is an apocalyptic number.

It is an amenable number.

221481 is a deficient number, since it is larger than the sum of its proper divisors (132439).

221481 is a wasteful number, since it uses less digits than its factorization.

221481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 653 (or 647 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 221481 is about 470.6176792259. The cubic root of 221481 is about 60.5032669046.

The spelling of 221481 in words is "two hundred twenty-one thousand, four hundred eighty-one".