217140720 has 80 divisors (see below), whose sum is σ = 682670592. Its totient is φ = 57084160.

The previous prime is 217140697. The next prime is 217140731. The reversal of 217140720 is 27041712.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 10669 + ... + 23411.

Almost surely, 2^217140720 is an apocalyptic number.

217140720 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 217140720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (341335296).

217140720 is an abundant number, since it is smaller than the sum of its proper divisors (465529872).

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

217140720 is a wasteful number, since it uses less digits than its factorization.

217140720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12830 (or 12824 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 24.

The square root of 217140720 is about 14735.6954365921. The cubic root of 217140720 is about 601.0543683160.

The spelling of 217140720 in words is "two hundred seventeen million, one hundred forty thousand, seven hundred twenty".