121555664 has 20 divisors (see below), whose sum is σ = 235689156. Its totient is φ = 60732672.

The previous prime is 121555649. The next prime is 121555699. The reversal of 121555664 is 466555121.

It can be written as a sum of positive squares in 2 ways, for example, as 91393600 + 30162064 = 9560^2 + 5492^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33692 + ... + 37124.

Almost surely, 2^121555664 is an apocalyptic number.

It is an amenable number.

121555664 is a deficient number, since it is larger than the sum of its proper divisors (114133492).

121555664 is a wasteful number, since it uses less digits than its factorization.

121555664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5654 (or 5648 counting only the distinct ones).

The product of its digits is 36000, while the sum is 35.

The square root of 121555664 is about 11025.2285237087. The cubic root of 121555664 is about 495.3647130202.

The spelling of 121555664 in words is "one hundred twenty-one million, five hundred fifty-five thousand, six hundred sixty-four".