121996997856 has 240 divisors, whose sum is σ = 379149724800. Its totient is φ = 38374808832.

The previous prime is 121996997839. The next prime is 121996997867. The reversal of 121996997856 is 658799699121.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 12947515 + ... + 12956933.

It is an arithmetic number, because the mean of its divisors is an integer number (1579790520).

Almost surely, 2^121996997856 is an apocalyptic number.

121996997856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121996997856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189574862400).

121996997856 is an abundant number, since it is smaller than the sum of its proper divisors (257152726944).

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

121996997856 is a wasteful number, since it uses less digits than its factorization.

121996997856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9723 (or 9706 counting only the distinct ones).

The product of its digits is 132269760, while the sum is 72.

The spelling of 121996997856 in words is "one hundred twenty-one billion, nine hundred ninety-six million, nine hundred ninety-seven thousand, eight hundred fifty-six".