221644461 has 4 divisors (see below), whose sum is σ = 295525952. Its totient is φ = 147762972.

The previous prime is 221644459. The next prime is 221644523. The reversal of 221644461 is 164446122.

It is a happy number.

221644461 is digitally balanced in base 2, 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 221644461 - 2¹ = 221644459 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 (221644441) 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, 36940741 + ... + 36940746.

It is an arithmetic number, because the mean of its divisors is an integer number (73881488).

Almost surely, 2^221644461 is an apocalyptic number.

It is an amenable number.

221644461 is a deficient number, since it is larger than the sum of its proper divisors (73881491).

221644461 is an equidigital number, since it uses as much as digits as its factorization.

221644461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73881490.

The product of its digits is 9216, while the sum is 30.

The square root of 221644461 is about 14887.7285372887. The cubic root of 221644461 is about 605.1814777847.

The spelling of 221644461 in words is "two hundred twenty-one million, six hundred forty-four thousand, four hundred sixty-one".