217903231 has 32 divisors (see below), whose sum is σ = 276756480. Its totient is φ = 166973184.

The previous prime is 217903223. The next prime is 217903237. The reversal of 217903231 is 132309712.

It is not a de Polignac number, because 217903231 - 2³ = 217903223 is a prime.

It is a super-2 number, since 2×217903231² = 94963636160478722, which contains 22 as substring.

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 217903231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217903237) 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 31 ways as a sum of consecutive naturals, for example, 911610 + ... + 911848.

It is an arithmetic number, because the mean of its divisors is an integer number (8648640).

Almost surely, 2^217903231 is an apocalyptic number.

217903231 is a deficient number, since it is larger than the sum of its proper divisors (58853249).

217903231 is a wasteful number, since it uses less digits than its factorization.

217903231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 217903231 is about 14761.5456846497. The cubic root of 217903231 is about 601.7571002342.

The spelling of 217903231 in words is "two hundred seventeen million, nine hundred three thousand, two hundred thirty-one".