12121756416 has 648 divisors, whose sum is σ = 45583521984. Its totient is φ = 3061739520.

The previous prime is 12121756399. The next prime is 12121756421. The reversal of 12121756416 is 61465712121.

12121756416 is a `hidden beast` number, since 1 + 2 + 1 + 2 + 1 + 7 + 5 + 641 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 53399695 + ... + 53399921.

Almost surely, 2^12121756416 is an apocalyptic number.

12121756416 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 12121756416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22791760992).

12121756416 is an abundant number, since it is smaller than the sum of its proper divisors (33461765568).

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

12121756416 is a wasteful number, since it uses less digits than its factorization.

12121756416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317 (or 293 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The spelling of 12121756416 in words is "twelve billion, one hundred twenty-one million, seven hundred fifty-six thousand, four hundred sixteen".