217481640 has 32 divisors (see below), whose sum is σ = 652445280. Its totient is φ = 57995072.

The previous prime is 217481639. The next prime is 217481669. The reversal of 217481640 is 46184712.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 906054 + ... + 906293.

It is an arithmetic number, because the mean of its divisors is an integer number (20388915).

Almost surely, 2^217481640 is an apocalyptic number.

217481640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217481640 is an abundant number, since it is smaller than the sum of its proper divisors (434963640).

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

217481640 is a wasteful number, since it uses less digits than its factorization.

217481640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812361 (or 1812357 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 217481640 is about 14747.2587283196. The cubic root of 217481640 is about 601.3687639897.

The spelling of 217481640 in words is "two hundred seventeen million, four hundred eighty-one thousand, six hundred forty".