221821894 has 8 divisors (see below), whose sum is σ = 380266128. Its totient is φ = 95066520.

The previous prime is 221821889. The next prime is 221821921. The reversal of 221821894 is 498128122.

It is a happy number.

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

It is a congruent number.

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, 7922197 + ... + 7922224.

It is an arithmetic number, because the mean of its divisors is an integer number (47533266).

Almost surely, 2^221821894 is an apocalyptic number.

221821894 is a deficient number, since it is larger than the sum of its proper divisors (158444234).

221821894 is a wasteful number, since it uses less digits than its factorization.

221821894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15844430.

The product of its digits is 18432, while the sum is 37.

The square root of 221821894 is about 14893.6863804768. The cubic root of 221821894 is about 605.3429233178.

The spelling of 221821894 in words is "two hundred twenty-one million, eight hundred twenty-one thousand, eight hundred ninety-four".