216121456 has 40 divisors (see below), whose sum is σ = 434570400. Its totient is φ = 103998720.

The previous prime is 216121441. The next prime is 216121469. The reversal of 216121456 is 654121612.

It is an alternating number because its digits alternate between even and odd.

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 203166 + ... + 204226.

It is an arithmetic number, because the mean of its divisors is an integer number (10864260).

Almost surely, 2^216121456 is an apocalyptic number.

216121456 is the 8488-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216121456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (217285200).

216121456 is an abundant number, since it is smaller than the sum of its proper divisors (218448944).

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

216121456 is a wasteful number, since it uses less digits than its factorization.

216121456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1537 (or 1531 counting only the distinct ones).

The product of its digits is 2880, while the sum is 28.

The square root of 216121456 is about 14701.0698930384. The cubic root of 216121456 is about 600.1124381874.

The spelling of 216121456 in words is "two hundred sixteen million, one hundred twenty-one thousand, four hundred fifty-six".