121720550106 has 16 divisors (see below), whose sum is σ = 243444537504. Its totient is φ = 40572943824.

The previous prime is 121720550101. The next prime is 121720550111. The reversal of 121720550106 is 601055027121.

It is an interprime number because it is at equal distance from previous prime (121720550101) and next prime (121720550111).

It is a super-2 number, since 2×121720550106² (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 7 ways as a sum of consecutive naturals, for example, 690165 + ... + 848391.

It is an arithmetic number, because the mean of its divisors is an integer number (15215283594).

Almost surely, 2^121720550106 is an apocalyptic number.

121720550106 is an abundant number, since it is smaller than the sum of its proper divisors (121723987398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121720550106 is a wasteful number, since it uses less digits than its factorization.

121720550106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286445.

The product of its (nonzero) digits is 4200, while the sum is 30.

Adding to 121720550106 its reverse (601055027121), we get a palindrome (722775577227).

The spelling of 121720550106 in words is "one hundred twenty-one billion, seven hundred twenty million, five hundred fifty thousand, one hundred six".