221381789 has 4 divisors (see below), whose sum is σ = 221668956. Its totient is φ = 221094624.

The previous prime is 221381777. The next prime is 221381791. The reversal of 221381789 is 987183122.

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

It can be written as a sum of positive squares in 2 ways, for example, as 119028100 + 102353689 = 10910^2 + 10117^2 .

It is a cyclic number.

It is not a de Polignac number, because 221381789 - 2⁴ = 221381773 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221341789) 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, 142424 + ... + 143969.

It is an arithmetic number, because the mean of its divisors is an integer number (55417239).

Almost surely, 2^221381789 is an apocalyptic number.

It is an amenable number.

221381789 is a deficient number, since it is larger than the sum of its proper divisors (287167).

221381789 is an equidigital number, since it uses as much as digits as its factorization.

221381789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287166.

The product of its digits is 48384, while the sum is 41.

The square root of 221381789 is about 14878.9041599172. The cubic root of 221381789 is about 604.9423153799.

The spelling of 221381789 in words is "two hundred twenty-one million, three hundred eighty-one thousand, seven hundred eighty-nine".