1221889 has 4 divisors (see below), whose sum is σ = 1233856. Its totient is φ = 1209924.

The previous prime is 1221863. The next prime is 1221907. The reversal of 1221889 is 9881221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9881221 = 7 ⋅1411603.

It is a cyclic number.

It is not a de Polignac number, because 1221889 - 2⁷ = 1221761 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221889.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5829 + ... + 6034.

It is an arithmetic number, because the mean of its divisors is an integer number (308464).

2^1221889 is an apocalyptic number.

It is an amenable number.

1221889 is a deficient number, since it is larger than the sum of its proper divisors (11967).

1221889 is a wasteful number, since it uses less digits than its factorization.

1221889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11966.

The product of its digits is 2304, while the sum is 31.

The square root of 1221889 is about 1105.3908810914. The cubic root of 1221889 is about 106.9080935556.

The spelling of 1221889 in words is "one million, two hundred twenty-one thousand, eight hundred eighty-nine".