121720550138 has 8 divisors (see below), whose sum is σ = 199179082080. Its totient is φ = 55327522780.

The previous prime is 121720550123. The next prime is 121720550173. The reversal of 121720550138 is 831055027121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121720550098 and 121720550107.

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, 2766376118 + ... + 2766376161.

It is an arithmetic number, because the mean of its divisors is an integer number (24897385260).

Almost surely, 2^121720550138 is an apocalyptic number.

121720550138 is a deficient number, since it is larger than the sum of its proper divisors (77458531942).

121720550138 is a wasteful number, since it uses less digits than its factorization.

121720550138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5532752292.

The product of its (nonzero) digits is 16800, while the sum is 35.

Adding to 121720550138 its reverse (831055027121), we get a palindrome (952775577259).

The spelling of 121720550138 in words is "one hundred twenty-one billion, seven hundred twenty million, five hundred fifty thousand, one hundred thirty-eight".