217265640 has 64 divisors (see below), whose sum is σ = 657927360. Its totient is φ = 57392640.

The previous prime is 217265623. The next prime is 217265647. The reversal of 217265640 is 46562712.

It is not an unprimeable number, because it can be changed into a prime (217265647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4380 + ... + 21300.

It is an arithmetic number, because the mean of its divisors is an integer number (10280115).

Almost surely, 2^217265640 is an apocalyptic number.

217265640 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 217265640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (328963680).

217265640 is an abundant number, since it is smaller than the sum of its proper divisors (440661720).

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

217265640 is a wasteful number, since it uses less digits than its factorization.

217265640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17042 (or 17038 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 217265640 is about 14739.9335140970. The cubic root of 217265640 is about 601.1696074381.

The spelling of 217265640 in words is "two hundred seventeen million, two hundred sixty-five thousand, six hundred forty".