121905469648561 has 9 divisors (see below), whose sum is σ = 127436418048121. Its totient is φ = 116604988933972.

The previous prime is 121905469648541. The next prime is 121905469648577. The reversal of 121905469648561 is 165846964509121.

The square root of 121905469648561 is 11041081.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 121905469648561 - 2⁷ = 121905469648433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121905469648511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 253704840 + ... + 254184886.

Almost surely, 2^{121905469648561} is an apocalyptic number.

121905469648561 is the 11041081-st square number.

121905469648561 is the 5520541-st centered octagonal number.

It is an amenable number.

121905469648561 is a deficient number, since it is larger than the sum of its proper divisors (5530948399560).

121905469648561 is an frugal number, since it uses more digits than its factorization.

121905469648561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 960140 (or 480070 counting only the distinct ones).

The product of its (nonzero) digits is 111974400, while the sum is 67.

The spelling of 121905469648561 in words is "one hundred twenty-one trillion, nine hundred five billion, four hundred sixty-nine million, six hundred forty-eight thousand, five hundred sixty-one".