1213561 has 2 divisors, whose sum is σ = 1213562. Its totient is φ = 1213560.

The previous prime is 1213547. The next prime is 1213573. The reversal of 1213561 is 1653121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 783225 + 430336 = 885^2 + 656^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213561 - 2⁵ = 1213529 is a prime.

It is not a weakly prime, because it can be changed into another prime (1213591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606780 + 606781.

It is an arithmetic number, because the mean of its divisors is an integer number (606781).

2^1213561 is an apocalyptic number.

It is an amenable number.

1213561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213561 is an equidigital number, since it uses as much as digits as its factorization.

1213561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 19.

The square root of 1213561 is about 1101.6174472111. The cubic root of 1213561 is about 106.6646559951.

Adding to 1213561 its reverse (1653121), we get a palindrome (2866682).

The spelling of 1213561 in words is "one million, two hundred thirteen thousand, five hundred sixty-one".