121663550661 has 16 divisors (see below), whose sum is σ = 164986329600. Its totient is φ = 79725216368.

The previous prime is 121663550629. The next prime is 121663550669. The reversal of 121663550661 is 166055366121.

It is a cyclic number.

It is not a de Polignac number, because 121663550661 - 2⁵ = 121663550629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121663550669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1747720 + ... + 1815998.

It is an arithmetic number, because the mean of its divisors is an integer number (10311645600).

Almost surely, 2^121663550661 is an apocalyptic number.

It is an amenable number.

121663550661 is a deficient number, since it is larger than the sum of its proper divisors (43322778939).

121663550661 is a wasteful number, since it uses less digits than its factorization.

121663550661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78408.

The product of its (nonzero) digits is 194400, while the sum is 42.

The spelling of 121663550661 in words is "one hundred twenty-one billion, six hundred sixty-three million, five hundred fifty thousand, six hundred sixty-one".