221478 has 8 divisors (see below), whose sum is σ = 442968. Its totient is φ = 73824.

The previous prime is 221477. The next prime is 221489. The reversal of 221478 is 874122.

It is a sphenic number, since it is the product of 3 distinct primes.

221478 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18451 + ... + 18462.

It is an arithmetic number, because the mean of its divisors is an integer number (55371).

2²²¹⁴⁷⁸ is an apocalyptic number.

221478 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

221478 is a wasteful number, since it uses less digits than its factorization.

221478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36918.

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

The square root of 221478 is about 470.6144919146. The cubic root of 221478 is about 60.5029937275.

It can be divided in two parts, 22147 and 8, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 221478 in words is "two hundred twenty-one thousand, four hundred seventy-eight".