217745971380 has 288 divisors, whose sum is σ = 758988921600. Its totient is φ = 49498767360.

The previous prime is 217745971379. The next prime is 217745971393. The reversal of 217745971380 is 83179547712.

217745971380 is a `hidden beast` number, since 2 + 17 + 7 + 4 + 597 + 1 + 38 + 0 = 666.

217745971380 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 315116835 + ... + 315117525.

It is an arithmetic number, because the mean of its divisors is an integer number (2635378200).

Almost surely, 2^217745971380 is an apocalyptic number.

217745971380 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 217745971380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379494460800).

217745971380 is an abundant number, since it is smaller than the sum of its proper divisors (541242950220).

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

217745971380 is a wasteful number, since it uses less digits than its factorization.

217745971380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719 (or 1714 counting only the distinct ones).

The product of its (nonzero) digits is 2963520, while the sum is 54.

The spelling of 217745971380 in words is "two hundred seventeen billion, seven hundred forty-five million, nine hundred seventy-one thousand, three hundred eighty".