217151440 has 60 divisors (see below), whose sum is σ = 554972292. Its totient is φ = 78960640.

The previous prime is 217151369. The next prime is 217151443. The reversal of 217151440 is 44151712.

It can be written as a sum of positive squares in 2 ways, for example, as 144288144 + 72863296 = 12012^2 + 8536^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217151443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1537 + ... + 20896.

Almost surely, 2^217151440 is an apocalyptic number.

217151440 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 217151440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (277486146).

217151440 is an abundant number, since it is smaller than the sum of its proper divisors (337820852).

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

217151440 is a wasteful number, since it uses less digits than its factorization.

217151440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22468 (or 22451 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 217151440 is about 14736.0591746912. The cubic root of 217151440 is about 601.0642592856.

The spelling of 217151440 in words is "two hundred seventeen million, one hundred fifty-one thousand, four hundred forty".