121663523665 has 16 divisors (see below), whose sum is σ = 146450304000. Its totient is φ = 97028240832.

The previous prime is 121663523647. The next prime is 121663523701. The reversal of 121663523665 is 566325366121.

It is a cyclic number.

It is not a de Polignac number, because 121663523665 - 2¹⁷ = 121663392593 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11970856 + ... + 11981014.

It is an arithmetic number, because the mean of its divisors is an integer number (9153144000).

Almost surely, 2^121663523665 is an apocalyptic number.

It is an amenable number.

121663523665 is a deficient number, since it is larger than the sum of its proper divisors (24786780335).

121663523665 is a wasteful number, since it uses less digits than its factorization.

121663523665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17376.

The product of its digits is 1166400, while the sum is 46.

Adding to 121663523665 its reverse (566325366121), we get a palindrome (687988889786).

The spelling of 121663523665 in words is "one hundred twenty-one billion, six hundred sixty-three million, five hundred twenty-three thousand, six hundred sixty-five".