1220561 has 4 divisors (see below), whose sum is σ = 1237824. Its totient is φ = 1203300.

The previous prime is 1220507. The next prime is 1220591. The reversal of 1220561 is 1650221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1220561 - 2⁶ = 1220497 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1220591) 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, 8525 + ... + 8666.

It is an arithmetic number, because the mean of its divisors is an integer number (309456).

2^1220561 is an apocalyptic number.

It is an amenable number.

1220561 is a deficient number, since it is larger than the sum of its proper divisors (17263).

1220561 is an equidigital number, since it uses as much as digits as its factorization.

1220561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17262.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1220561 is about 1104.7900252989. The cubic root of 1220561 is about 106.8693487887.

Adding to 1220561 its reverse (1650221), we get a palindrome (2870782).

The spelling of 1220561 in words is "one million, two hundred twenty thousand, five hundred sixty-one".