217238440 has 16 divisors (see below), whose sum is σ = 488786580. Its totient is φ = 86895360.

The previous prime is 217238431. The next prime is 217238447. The reversal of 217238440 is 44832712.

It can be written as a sum of positive squares in 2 ways, for example, as 193599396 + 23639044 = 13914^2 + 4862^2 .

It is not an unprimeable number, because it can be changed into a prime (217238447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2715441 + ... + 2715520.

Almost surely, 2^217238440 is an apocalyptic number.

217238440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217238440 is an abundant number, since it is smaller than the sum of its proper divisors (271548140).

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

217238440 is a wasteful number, since it uses less digits than its factorization.

217238440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5430972 (or 5430968 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 217238440 is about 14739.0108216257. The cubic root of 217238440 is about 601.1445191089.

The spelling of 217238440 in words is "two hundred seventeen million, two hundred thirty-eight thousand, four hundred forty".