217240992 has 72 divisors (see below), whose sum is σ = 626302404. Its totient is φ = 71414784.

The previous prime is 217240987. The next prime is 217240999. The reversal of 217240992 is 299042712.

217240992 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 211877136 + 5363856 = 14556^2 + 2316^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (217240999) 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, 15858 + ... + 26190.

Almost surely, 2^217240992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217240992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313151202).

217240992 is an abundant number, since it is smaller than the sum of its proper divisors (409061412).

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

217240992 is a wasteful number, since it uses less digits than its factorization.

217240992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10422 (or 10411 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 217240992 is about 14739.0973943454. The cubic root of 217240992 is about 601.1468730735.

The spelling of 217240992 in words is "two hundred seventeen million, two hundred forty thousand, nine hundred ninety-two".