121257216 has 144 divisors (see below), whose sum is σ = 366448320. Its totient is φ = 39536640.

The previous prime is 121257121. The next prime is 121257217. The reversal of 121257216 is 612752121.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 121257216.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121257217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 366171 + ... + 366501.

It is an arithmetic number, because the mean of its divisors is an integer number (2544780).

Almost surely, 2^121257216 is an apocalyptic number.

121257216 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 121257216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (183224160).

121257216 is an abundant number, since it is smaller than the sum of its proper divisors (245191104).

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

121257216 is an equidigital number, since it uses as much as digits as its factorization.

121257216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 389 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 121257216 is about 11011.6854295789. The cubic root of 121257216 is about 494.9589681324.

The spelling of 121257216 in words is "one hundred twenty-one million, two hundred fifty-seven thousand, two hundred sixteen".