216538231 has 64 divisors (see below), whose sum is σ = 304819200. Its totient is φ = 148801536.

The previous prime is 216538229. The next prime is 216538237. The reversal of 216538231 is 132835612.

It is not a de Polignac number, because 216538231 - 2¹ = 216538229 is a prime.

It is a super-2 number, since 2×216538231² = 93777610969218722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 216538193 and 216538202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216538237) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1557760 + ... + 1557898.

It is an arithmetic number, because the mean of its divisors is an integer number (4762800).

Almost surely, 2^216538231 is an apocalyptic number.

216538231 is a deficient number, since it is larger than the sum of its proper divisors (88280969).

216538231 is a wasteful number, since it uses less digits than its factorization.

216538231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248.

The product of its digits is 8640, while the sum is 31.

The square root of 216538231 is about 14715.2380544794. The cubic root of 216538231 is about 600.4979486679.

The spelling of 216538231 in words is "two hundred sixteen million, five hundred thirty-eight thousand, two hundred thirty-one".