121660551 has 24 divisors (see below), whose sum is σ = 191106864. Its totient is φ = 74269440.

The previous prime is 121660541. The next prime is 121660573. The reversal of 121660551 is 155066121.

It is a happy number.

121660551 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 605 + 51 = 666.

It is not a de Polignac number, because 121660551 - 2⁹ = 121660039 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121660531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5085 + ... + 16406.

It is an arithmetic number, because the mean of its divisors is an integer number (7962786).

Almost surely, 2^121660551 is an apocalyptic number.

121660551 is a deficient number, since it is larger than the sum of its proper divisors (69446313).

121660551 is a wasteful number, since it uses less digits than its factorization.

121660551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21551 (or 21548 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 121660551 is about 11029.9841794991. The cubic root of 121660551 is about 495.5071508684.

The spelling of 121660551 in words is "one hundred twenty-one million, six hundred sixty thousand, five hundred fifty-one".