1205921 has 2 divisors, whose sum is σ = 1205922. Its totient is φ = 1205920.

The previous prime is 1205903. The next prime is 1205947. The reversal of 1205921 is 1295021.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 664225 + 541696 = 815^2 + 736^2 .

It is a cyclic number.

It is not a de Polignac number, because 1205921 - 2¹⁸ = 943777 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1205893 and 1205902.

It is not a weakly prime, because it can be changed into another prime (1205951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602960 + 602961.

It is an arithmetic number, because the mean of its divisors is an integer number (602961).

2^1205921 is an apocalyptic number.

It is an amenable number.

1205921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205921 is an equidigital number, since it uses as much as digits as its factorization.

1205921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 1205921 is about 1098.1443438820. The cubic root of 1205921 is about 106.4403480590.

The spelling of 1205921 in words is "one million, two hundred five thousand, nine hundred twenty-one".