1217621 has 4 divisors (see below), whose sum is σ = 1237644. Its totient is φ = 1197600.

The previous prime is 1217617. The next prime is 1217647. The reversal of 1217621 is 1267121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 555025 + 662596 = 745^2 + 814^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217621 - 2² = 1217617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1217593 and 1217602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217651) 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, 9920 + ... + 10041.

It is an arithmetic number, because the mean of its divisors is an integer number (309411).

2^1217621 is an apocalyptic number.

It is an amenable number.

1217621 is a deficient number, since it is larger than the sum of its proper divisors (20023).

1217621 is an equidigital number, since it uses as much as digits as its factorization.

1217621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20022.

The product of its digits is 168, while the sum is 20.

The square root of 1217621 is about 1103.4586535072. The cubic root of 1217621 is about 106.7834733881.

The spelling of 1217621 in words is "one million, two hundred seventeen thousand, six hundred twenty-one".