121666816 has 36 divisors (see below), whose sum is σ = 250708864. Its totient is φ = 58867200.

The previous prime is 121666813. The next prime is 121666829. The reversal of 121666816 is 618666121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121666813) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271 + ... + 15601.

Almost surely, 2^121666816 is an apocalyptic number.

121666816 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 121666816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125354432).

121666816 is an abundant number, since it is smaller than the sum of its proper divisors (129042048).

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

121666816 is an equidigital number, since it uses as much as digits as its factorization.

121666816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15378 (or 15364 counting only the distinct ones).

The product of its digits is 20736, while the sum is 37.

The square root of 121666816 is about 11030.2681744371. The cubic root of 121666816 is about 495.5156562247.

The spelling of 121666816 in words is "one hundred twenty-one million, six hundred sixty-six thousand, eight hundred sixteen".