221005478 has 4 divisors (see below), whose sum is σ = 331508220. Its totient is φ = 110502738.

The previous prime is 221005471. The next prime is 221005481. The reversal of 221005478 is 874500122.

221005478 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 221005478.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221005471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55251368 + ... + 55251371.

It is an arithmetic number, because the mean of its divisors is an integer number (82877055).

Almost surely, 2^221005478 is an apocalyptic number.

221005478 is a deficient number, since it is larger than the sum of its proper divisors (110502742).

221005478 is a wasteful number, since it uses less digits than its factorization.

221005478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110502741.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 221005478 is about 14866.2529912551. The cubic root of 221005478 is about 604.5993549867.

The spelling of 221005478 in words is "two hundred twenty-one million, five thousand, four hundred seventy-eight".