1251221 has 4 divisors (see below), whose sum is σ = 1260492. Its totient is φ = 1241952.

The previous prime is 1251179. The next prime is 1251227. The reversal of 1251221 is 1221521.

1251221 = 19² + 20² + ... + 155².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 874225 + 376996 = 935^2 + 614^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251221 - 2⁶ = 1251157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1251196 and 1251205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4430 + ... + 4703.

It is an arithmetic number, because the mean of its divisors is an integer number (315123).

2^1251221 is an apocalyptic number.

It is an amenable number.

1251221 is a deficient number, since it is larger than the sum of its proper divisors (9271).

1251221 is an equidigital number, since it uses as much as digits as its factorization.

1251221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9270.

The product of its digits is 40, while the sum is 14.

The square root of 1251221 is about 1118.5799032702. The cubic root of 1251221 is about 107.7567972844.

Adding to 1251221 its reverse (1221521), we get a palindrome (2472742).

The spelling of 1251221 in words is "one million, two hundred fifty-one thousand, two hundred twenty-one".