121720550105 has 64 divisors (see below), whose sum is σ = 186682599936. Its totient is φ = 73973760000.

The previous prime is 121720550101. The next prime is 121720550111. The reversal of 121720550105 is 501055027121.

It is not a de Polignac number, because 121720550105 - 2² = 121720550101 is a prime.

It is a super-2 number, since 2×121720550105² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (121720550101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 43454705 + ... + 43457505.

It is an arithmetic number, because the mean of its divisors is an integer number (2916915624).

Almost surely, 2^121720550105 is an apocalyptic number.

It is an amenable number.

121720550105 is a deficient number, since it is larger than the sum of its proper divisors (64962049831).

121720550105 is a wasteful number, since it uses less digits than its factorization.

121720550105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5618.

The product of its (nonzero) digits is 3500, while the sum is 29.

Adding to 121720550105 its reverse (501055027121), we get a palindrome (622775577226).

The spelling of 121720550105 in words is "one hundred twenty-one billion, seven hundred twenty million, five hundred fifty thousand, one hundred five".