1221291 has 8 divisors (see below), whose sum is σ = 1809360. Its totient is φ = 814176.

The previous prime is 1221289. The next prime is 1221299. The reversal of 1221291 is 1921221.

It is not a de Polignac number, because 1221291 - 2¹ = 1221289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221299) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22590 + ... + 22643.

It is an arithmetic number, because the mean of its divisors is an integer number (226170).

2^1221291 is an apocalyptic number.

1221291 is a deficient number, since it is larger than the sum of its proper divisors (588069).

1221291 is an equidigital number, since it uses as much as digits as its factorization.

1221291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45242 (or 45236 counting only the distinct ones).

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

The square root of 1221291 is about 1105.1203554365. The cubic root of 1221291 is about 106.8906502166.

The spelling of 1221291 in words is "one million, two hundred twenty-one thousand, two hundred ninety-one".