216526640 has 80 divisors (see below), whose sum is σ = 552420000. Its totient is φ = 78274560.

The previous prime is 216526633. The next prime is 216526649. The reversal of 216526640 is 46625612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 216526597 and 216526606.

It is not an unprimeable number, because it can be changed into a prime (216526649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 172736 + ... + 173984.

It is an arithmetic number, because the mean of its divisors is an integer number (6905250).

Almost surely, 2^216526640 is an apocalyptic number.

216526640 is a gapful number since it is divisible by the number (20) 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 216526640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276210000).

216526640 is an abundant number, since it is smaller than the sum of its proper divisors (335893360).

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

216526640 is a wasteful number, since it uses less digits than its factorization.

216526640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1470 (or 1464 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 216526640 is about 14714.8442057672. The cubic root of 216526640 is about 600.4872338611.

The spelling of 216526640 in words is "two hundred sixteen million, five hundred twenty-six thousand, six hundred forty".