217028906640 has 360 divisors, whose sum is σ = 913073543928. Its totient is φ = 45790617600.

The previous prime is 217028906639. The next prime is 217028906657. The reversal of 217028906640 is 46609820712.

It is a happy number.

217028906640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 14388482304 + 202640424336 = 119952^2 + 450156^2 .

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 222040 + ... + 695240.

Almost surely, 2^217028906640 is an apocalyptic number.

217028906640 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 217028906640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (456536771964).

217028906640 is an abundant number, since it is smaller than the sum of its proper divisors (696044637288).

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

217028906640 is a wasteful number, since it uses less digits than its factorization.

217028906640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473247 (or 473231 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 217028906640 in words is "two hundred seventeen billion, twenty-eight million, nine hundred six thousand, six hundred forty".