121285561 has 2 divisors, whose sum is σ = 121285562. Its totient is φ = 121285560.

The previous prime is 121285559. The next prime is 121285583. The reversal of 121285561 is 165582121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71723961 + 49561600 = 8469^2 + 7040^2 .

It is a cyclic number.

It is not a de Polignac number, because 121285561 - 2¹ = 121285559 is a prime.

Together with 121285559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (121285261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60642780 + 60642781.

It is an arithmetic number, because the mean of its divisors is an integer number (60642781).

Almost surely, 2^121285561 is an apocalyptic number.

It is an amenable number.

121285561 is a deficient number, since it is larger than the sum of its proper divisors (1).

121285561 is an equidigital number, since it uses as much as digits as its factorization.

121285561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 31.

The square root of 121285561 is about 11012.9723962244. The cubic root of 121285561 is about 494.9975322123.

It can be divided in two parts, 12128 and 5561, that added together give a square (17689 = 133²).

The spelling of 121285561 in words is "one hundred twenty-one million, two hundred eighty-five thousand, five hundred sixty-one".