216406940 has 48 divisors (see below), whose sum is σ = 482503392. Its totient is φ = 81248256.

The previous prime is 216406937. The next prime is 216406951. The reversal of 216406940 is 49604612.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 216406897 and 216406906.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177212 + ... + 178428.

It is an arithmetic number, because the mean of its divisors is an integer number (10052154).

Almost surely, 2^216406940 is an apocalyptic number.

216406940 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 216406940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241251696).

216406940 is an abundant number, since it is smaller than the sum of its proper divisors (266096452).

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

216406940 is a wasteful number, since it uses less digits than its factorization.

216406940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1766 (or 1764 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 216406940 is about 14710.7763221388. The cubic root of 216406940 is about 600.3765599179.

The spelling of 216406940 in words is "two hundred sixteen million, four hundred six thousand, nine hundred forty".