1001221 has 4 divisors (see below), whose sum is σ = 1078252. Its totient is φ = 924192.

The previous prime is 1001219. The next prime is 1001237. The reversal of 1001221 is 1221001.

1001221 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 an emirpimes, since its reverse is a distinct semiprime: 1221001 = 23 ⋅53087.

It can be written as a sum of positive squares in 2 ways, for example, as 592900 + 408321 = 770^2 + 639^2 .

It is a cyclic number.

It is not a de Polignac number, because 1001221 - 2¹ = 1001219 is a prime.

It is a Duffinian number.

1001221 is a modest number, since divided by 1221 gives 1 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001291) 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, 38496 + ... + 38521.

It is an arithmetic number, because the mean of its divisors is an integer number (269563).

2^1001221 is an apocalyptic number.

It is an amenable number.

1001221 is a deficient number, since it is larger than the sum of its proper divisors (77031).

1001221 is an equidigital number, since it uses as much as digits as its factorization.

1001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77030.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 1001221 is about 1000.6103137586. The cubic root of 1001221 is about 100.0406834463.

Adding to 1001221 its reverse (1221001), we get a palindrome (2222222).

The spelling of 1001221 in words is "one million, one thousand, two hundred twenty-one".