221298721 has 8 divisors (see below), whose sum is σ = 253462784. Its totient is φ = 189272160.

The previous prime is 221298713. The next prime is 221298731. The reversal of 221298721 is 127892122.

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

It is not a de Polignac number, because 221298721 - 2³ = 221298713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221298731) 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, 30900 + ... + 37381.

It is an arithmetic number, because the mean of its divisors is an integer number (31682848).

Almost surely, 2^221298721 is an apocalyptic number.

It is an amenable number.

221298721 is a deficient number, since it is larger than the sum of its proper divisors (32164063).

221298721 is an equidigital number, since it uses as much as digits as its factorization.

221298721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68751.

The product of its digits is 8064, while the sum is 34.

The square root of 221298721 is about 14876.1124289917. The cubic root of 221298721 is about 604.8666427376.

The spelling of 221298721 in words is "two hundred twenty-one million, two hundred ninety-eight thousand, seven hundred twenty-one".