217366381920 has 384 divisors, whose sum is σ = 751674349440. Its totient is φ = 52554629120.

The previous prime is 217366381889. The next prime is 217366381961. The reversal of 217366381920 is 29183663712.

It is a super-3 number, since 3×217366381920³ (a number of 35 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 217366381920.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 151685524 + ... + 151686956.

It is an arithmetic number, because the mean of its divisors is an integer number (1957485285).

Almost surely, 2^217366381920 is an apocalyptic number.

217366381920 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 217366381920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (375837174720).

217366381920 is an abundant number, since it is smaller than the sum of its proper divisors (534307967520).

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

217366381920 is a wasteful number, since it uses less digits than its factorization.

217366381920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2138 (or 2130 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 48.

The spelling of 217366381920 in words is "two hundred seventeen billion, three hundred sixty-six million, three hundred eighty-one thousand, nine hundred twenty".