222721 has 4 divisors (see below), whose sum is σ = 223792. Its totient is φ = 221652.

The previous prime is 222713. The next prime is 222731. The reversal of 222721 is 127222.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 127222 = 2 ⋅63611.

It is a cyclic number.

It is not a de Polignac number, because 222721 - 2³ = 222713 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 222695 and 222704.

It is not an unprimeable number, because it can be changed into a prime (222731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111 + ... + 676.

It is an arithmetic number, because the mean of its divisors is an integer number (55948).

It is a Proth number, since it is equal to 435 ⋅ 2⁹ + 1 and 435 < 2⁹.

2²²²⁷²¹ is an apocalyptic number.

It is an amenable number.

222721 is a deficient number, since it is larger than the sum of its proper divisors (1071).

222721 is an equidigital number, since it uses as much as digits as its factorization.

222721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070.

The product of its digits is 112, while the sum is 16.

The square root of 222721 is about 471.9332579931. The cubic root of 222721 is about 60.6159695339.

Adding to 222721 its reverse (127222), we get a palindrome (349943).

The spelling of 222721 in words is "two hundred twenty-two thousand, seven hundred twenty-one", and thus it is an iban number.