221027721 has 8 divisors (see below), whose sum is σ = 298740960. Its totient is φ = 145333152.

The previous prime is 221027713. The next prime is 221027743. The reversal of 221027721 is 127720122.

221027721 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 not a de Polignac number, because 221027721 - 2³ = 221027713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221027691 and 221027700.

It is not an unprimeable number, because it can be changed into a prime (221027711) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 504411 + ... + 504848.

It is an arithmetic number, because the mean of its divisors is an integer number (37342620).

Almost surely, 2^221027721 is an apocalyptic number.

It is an amenable number.

221027721 is a deficient number, since it is larger than the sum of its proper divisors (77713239).

221027721 is a wasteful number, since it uses less digits than its factorization.

221027721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009335.

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 221027721 is about 14867.0010762090. The cubic root of 221027721 is about 604.6196375191.

Adding to 221027721 its reverse (127720122), we get a palindrome (348747843).

The spelling of 221027721 in words is "two hundred twenty-one million, twenty-seven thousand, seven hundred twenty-one".