217229440 has 64 divisors (see below), whose sum is σ = 523480320. Its totient is φ = 86195200.

The previous prime is 217229393. The next prime is 217229461. The reversal of 217229440 is 44922712.

217229440 = T₃₁₅ + T₃₁₆ + ... + T₁₁₀₀.

217229440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

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, 82545 + ... + 85135.

It is an arithmetic number, because the mean of its divisors is an integer number (8179380).

Almost surely, 2^217229440 is an apocalyptic number.

217229440 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 217229440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (261740160).

217229440 is an abundant number, since it is smaller than the sum of its proper divisors (306250880).

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

217229440 is a wasteful number, since it uses less digits than its factorization.

217229440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2741 (or 2729 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 217229440 is about 14738.7055062512. The cubic root of 217229440 is about 601.1362173624.

The spelling of 217229440 in words is "two hundred seventeen million, two hundred twenty-nine thousand, four hundred forty".