221821378 has 8 divisors (see below), whose sum is σ = 332796672. Its totient is φ = 110889156.

The previous prime is 221821367. The next prime is 221821381. The reversal of 221821378 is 873128122.

221821378 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10551 + ... + 23557.

It is an arithmetic number, because the mean of its divisors is an integer number (41599584).

Almost surely, 2^221821378 is an apocalyptic number.

221821378 is a deficient number, since it is larger than the sum of its proper divisors (110975294).

221821378 is a wasteful number, since it uses less digits than its factorization.

221821378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21536.

The product of its digits is 10752, while the sum is 34.

The square root of 221821378 is about 14893.6690576903. The cubic root of 221821378 is about 605.3424539364.

The spelling of 221821378 in words is "two hundred twenty-one million, eight hundred twenty-one thousand, three hundred seventy-eight".