216660231 has 8 divisors (see below), whose sum is σ = 320978160. Its totient is φ = 144440136.

The previous prime is 216660229. The next prime is 216660239. The reversal of 216660231 is 132066612.

It is not a de Polignac number, because 216660231 - 2¹ = 216660229 is a prime.

It is a super-2 number, since 2×216660231² = 93883311393946722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 8024453 = 216660231 / (2 + 1 + 6 + 6 + 6 + 0 + 2 + 3 + 1).

It is a junction number, because it is equal to n+sod(n) for n = 216660195 and 216660204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216660239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4012200 + ... + 4012253.

It is an arithmetic number, because the mean of its divisors is an integer number (40122270).

Almost surely, 2^216660231 is an apocalyptic number.

216660231 is a deficient number, since it is larger than the sum of its proper divisors (104317929).

216660231 is an equidigital number, since it uses as much as digits as its factorization.

216660231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8024462 (or 8024456 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 216660231 is about 14719.3828335294. The cubic root of 216660231 is about 600.6107031918.

The spelling of 216660231 in words is "two hundred sixteen million, six hundred sixty thousand, two hundred thirty-one".