217028431 has 16 divisors (see below), whose sum is σ = 237283200. Its totient is φ = 197715168.

The previous prime is 217028419. The next prime is 217028459. The reversal of 217028431 is 134820712.

It is a cyclic number.

It is not a de Polignac number, because 217028431 - 2¹⁹ = 216504143 is a prime.

It is a super-2 number, since 2×217028431² = 94202679724643522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 217028431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217028401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 168516 + ... + 169798.

It is an arithmetic number, because the mean of its divisors is an integer number (14830200).

Almost surely, 2^217028431 is an apocalyptic number.

217028431 is a deficient number, since it is larger than the sum of its proper divisors (20254769).

217028431 is a wasteful number, since it uses less digits than its factorization.

217028431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 217028431 is about 14731.8848420696. The cubic root of 217028431 is about 600.9507436078.

The spelling of 217028431 in words is "two hundred seventeen million, twenty-eight thousand, four hundred thirty-one".