121585721 has 2 divisors, whose sum is σ = 121585722. Its totient is φ = 121585720.

The previous prime is 121585699. The next prime is 121585727. The reversal of 121585721 is 127585121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 92544400 + 29041321 = 9620^2 + 5389^2 .

It is a cyclic number.

It is not a de Polignac number, because 121585721 - 2¹⁴ = 121569337 is a prime.

It is not a weakly prime, because it can be changed into another prime (121585727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60792860 + 60792861.

It is an arithmetic number, because the mean of its divisors is an integer number (60792861).

Almost surely, 2^121585721 is an apocalyptic number.

It is an amenable number.

121585721 is a deficient number, since it is larger than the sum of its proper divisors (1).

121585721 is an equidigital number, since it uses as much as digits as its factorization.

121585721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5600, while the sum is 32.

The square root of 121585721 is about 11026.5915404535. The cubic root of 121585721 is about 495.4055391725.

The spelling of 121585721 in words is "one hundred twenty-one million, five hundred eighty-five thousand, seven hundred twenty-one".