1221331 has 4 divisors (see below), whose sum is σ = 1293192. Its totient is φ = 1149472.

The previous prime is 1221299. The next prime is 1221373. The reversal of 1221331 is 1331221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1331221 = 163 ⋅8167.

It is not a de Polignac number, because 1221331 - 2⁵ = 1221299 is a prime.

It is a super-2 number, since 2×1221331² = 2983298823122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221391) 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, 35905 + ... + 35938.

It is an arithmetic number, because the mean of its divisors is an integer number (323298).

2^1221331 is an apocalyptic number.

1221331 is a deficient number, since it is larger than the sum of its proper divisors (71861).

1221331 is an equidigital number, since it uses as much as digits as its factorization.

1221331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71860.

The product of its digits is 36, while the sum is 13.

The square root of 1221331 is about 1105.1384528646. The cubic root of 1221331 is about 106.8918171728.

Adding to 1221331 its reverse (1331221), we get a palindrome (2552552).

The spelling of 1221331 in words is "one million, two hundred twenty-one thousand, three hundred thirty-one".