1221389 has 8 divisors (see below), whose sum is σ = 1344000. Its totient is φ = 1102896.

The previous prime is 1221383. The next prime is 1221391. The reversal of 1221389 is 9831221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221389 - 2⁴ = 1221373 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221383) 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, 389 + ... + 1610.

It is an arithmetic number, because the mean of its divisors is an integer number (168000).

2^1221389 is an apocalyptic number.

It is an amenable number.

1221389 is a deficient number, since it is larger than the sum of its proper divisors (122611).

1221389 is a wasteful number, since it uses less digits than its factorization.

1221389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2059.

The product of its digits is 864, while the sum is 26.

The square root of 1221389 is about 1105.1646936091. The cubic root of 1221389 is about 106.8935092141.

The spelling of 1221389 in words is "one million, two hundred twenty-one thousand, three hundred eighty-nine".