221487 has 16 divisors (see below), whose sum is σ = 345600. Its totient is φ = 123552.

The previous prime is 221477. The next prime is 221489. The reversal of 221487 is 784122.

It is not a de Polignac number, because 221487 - 2⁴ = 221471 is a prime.

It is an Ulam number.

It is a congruent 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, 1014 + ... + 1212.

It is an arithmetic number, because the mean of its divisors is an integer number (21600).

2²²¹⁴⁸⁷ is an apocalyptic number.

221487 is a deficient number, since it is larger than the sum of its proper divisors (124113).

221487 is a wasteful number, since it uses less digits than its factorization.

221487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262.

The product of its digits is 896, while the sum is 24.

The square root of 221487 is about 470.6240537839. The cubic root of 221487 is about 60.5038132514.

It can be divided in two parts, 22148 and 7, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 221487 in words is "two hundred twenty-one thousand, four hundred eighty-seven".