217078920 has 192 divisors, whose sum is σ = 752544000. Its totient is φ = 55657728.

The previous prime is 217078909. The next prime is 217078943. The reversal of 217078920 is 29870712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 908161 + ... + 908399.

It is an arithmetic number, because the mean of its divisors is an integer number (3919500).

Almost surely, 2^217078920 is an apocalyptic number.

217078920 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 217078920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (376272000).

217078920 is an abundant number, since it is smaller than the sum of its proper divisors (535465080).

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

217078920 is a wasteful number, since it uses less digits than its factorization.

217078920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 217078920 is about 14733.5983384915. The cubic root of 217078920 is about 600.9973412654.

The spelling of 217078920 in words is "two hundred seventeen million, seventy-eight thousand, nine hundred twenty".