121561361 has 2 divisors, whose sum is σ = 121561362. Its totient is φ = 121561360.

The previous prime is 121561343. The next prime is 121561367. The reversal of 121561361 is 163165121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120670225 + 891136 = 10985^2 + 944^2 .

It is a cyclic number.

It is not a de Polignac number, because 121561361 - 2¹⁰ = 121560337 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121561361.

It is not a weakly prime, because it can be changed into another prime (121561367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60780680 + 60780681.

It is an arithmetic number, because the mean of its divisors is an integer number (60780681).

Almost surely, 2^121561361 is an apocalyptic number.

It is an amenable number.

121561361 is a deficient number, since it is larger than the sum of its proper divisors (1).

121561361 is an equidigital number, since it uses as much as digits as its factorization.

121561361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 26.

The square root of 121561361 is about 11025.4868826733. The cubic root of 121561361 is about 495.3724517209.

The spelling of 121561361 in words is "one hundred twenty-one million, five hundred sixty-one thousand, three hundred sixty-one".