121720550123 has 2 divisors, whose sum is σ = 121720550124. Its totient is φ = 121720550122.

The previous prime is 121720550111. The next prime is 121720550173. The reversal of 121720550123 is 321055027121.

It is a weak prime.

It is an emirp because it is prime and its reverse (321055027121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 121720550123 - 2¹² = 121720546027 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (121720550173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60860275061 + 60860275062.

It is an arithmetic number, because the mean of its divisors is an integer number (60860275062).

Almost surely, 2^121720550123 is an apocalyptic number.

121720550123 is a deficient number, since it is larger than the sum of its proper divisors (1).

121720550123 is an equidigital number, since it uses as much as digits as its factorization.

121720550123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4200, while the sum is 29.

Adding to 121720550123 its reverse (321055027121), we get a palindrome (442775577244).

The spelling of 121720550123 in words is "one hundred twenty-one billion, seven hundred twenty million, five hundred fifty thousand, one hundred twenty-three".