1221305 has 4 divisors (see below), whose sum is σ = 1465572. Its totient is φ = 977040.

The previous prime is 1221299. The next prime is 1221373. The reversal of 1221305 is 5031221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5031221 = 13 ⋅387017.

It can be written as a sum of positive squares in 2 ways, for example, as 946729 + 274576 = 973^2 + 524^2 .

It is not a de Polignac number, because 1221305 - 2⁴ = 1221289 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 1221305.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122126 + ... + 122135.

It is an arithmetic number, because the mean of its divisors is an integer number (366393).

2^1221305 is an apocalyptic number.

It is an amenable number.

1221305 is a deficient number, since it is larger than the sum of its proper divisors (244267).

1221305 is an equidigital number, since it uses as much as digits as its factorization.

1221305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244266.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 1221305 is about 1105.1266895700. The cubic root of 1221305 is about 106.8910586542.

Adding to 1221305 its reverse (5031221), we get a palindrome (6252526).

The spelling of 1221305 in words is "one million, two hundred twenty-one thousand, three hundred five".