217130400 has 216 divisors, whose sum is σ = 781473420. Its totient is φ = 56709120.

The previous prime is 217130359. The next prime is 217130413. The reversal of 217130400 is 4031712.

It can be written as a sum of positive squares in 6 ways, for example, as 64064016 + 153066384 = 8004^2 + 12372^2 .

It is a super-2 number, since 2×217130400² = 94291221208320000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 381316 + ... + 381884.

Almost surely, 2^217130400 is an apocalyptic number.

217130400 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 217130400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (390736710).

217130400 is an abundant number, since it is smaller than the sum of its proper divisors (564343020).

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

217130400 is a wasteful number, since it uses less digits than its factorization.

217130400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648 (or 632 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 217130400 is about 14735.3452623276. The cubic root of 217130400 is about 601.0448461049.

The spelling of 217130400 in words is "two hundred seventeen million, one hundred thirty thousand, four hundred".