1291221 has 20 divisors (see below), whose sum is σ = 2032800. Its totient is φ = 814536.

The previous prime is 1291219. The next prime is 1291223. The reversal of 1291221 is 1221921.

It is an interprime number because it is at equal distance from previous prime (1291219) and next prime (1291223).

It is not a de Polignac number, because 1291221 - 2¹ = 1291219 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1291194 and 1291203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1120 + ... + 1958.

It is an arithmetic number, because the mean of its divisors is an integer number (101640).

2^1291221 is an apocalyptic number.

It is an amenable number.

1291221 is a deficient number, since it is larger than the sum of its proper divisors (741579).

1291221 is an equidigital number, since it uses as much as digits as its factorization.

1291221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870 (or 861 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

The square root of 1291221 is about 1136.3190573074. The cubic root of 1291221 is about 108.8930578640.

The spelling of 1291221 in words is "one million, two hundred ninety-one thousand, two hundred twenty-one".