121719081816 has 192 divisors, whose sum is σ = 365425632000. Its totient is φ = 36428071680.

The previous prime is 121719081727. The next prime is 121719081829. The reversal of 121719081816 is 618180917121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3411831 + ... + 3447321.

It is an arithmetic number, because the mean of its divisors is an integer number (1903258500).

Almost surely, 2^121719081816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121719081816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (182712816000).

121719081816 is an abundant number, since it is smaller than the sum of its proper divisors (243706550184).

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

121719081816 is a wasteful number, since it uses less digits than its factorization.

121719081816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35654 (or 35647 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 45.

Adding to 121719081816 its reverse (618180917121), we get a palindrome (739899998937).

The spelling of 121719081816 in words is "one hundred twenty-one billion, seven hundred nineteen million, eighty-one thousand, eight hundred sixteen".