1220921 has 8 divisors (see below), whose sum is σ = 1384320. Its totient is φ = 1067472.

The previous prime is 1220917. The next prime is 1220927. The reversal of 1220921 is 1290221.

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 1220921 - 2² = 1220917 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1220921.

It is not an unprimeable number, because it can be changed into a prime (1220927) 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, 2225 + ... + 2718.

It is an arithmetic number, because the mean of its divisors is an integer number (173040).

2^1220921 is an apocalyptic number.

It is an amenable number.

1220921 is a deficient number, since it is larger than the sum of its proper divisors (163399).

1220921 is a wasteful number, since it uses less digits than its factorization.

1220921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4975.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1220921 is about 1104.9529401744. The cubic root of 1220921 is about 106.8798546636.

The spelling of 1220921 in words is "one million, two hundred twenty thousand, nine hundred twenty-one".