1221761 has 2 divisors, whose sum is σ = 1221762. Its totient is φ = 1221760.

The previous prime is 1221751. The next prime is 1221767. The reversal of 1221761 is 1671221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 891136 + 330625 = 944^2 + 575^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221761 - 2¹⁴ = 1205377 is a prime.

It is a super-2 number, since 2×1221761² = 2985399882242, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1221767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610880 + 610881.

It is an arithmetic number, because the mean of its divisors is an integer number (610881).

2^1221761 is an apocalyptic number.

It is an amenable number.

1221761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221761 is an equidigital number, since it uses as much as digits as its factorization.

1221761 is an odious number, because the sum of its binary digits is odd.

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

The square root of 1221761 is about 1105.3329815038. The cubic root of 1221761 is about 106.9043603431.

Adding to 1221761 its reverse (1671221), we get a palindrome (2892982).

The spelling of 1221761 in words is "one million, two hundred twenty-one thousand, seven hundred sixty-one".