216911538 has 24 divisors (see below), whose sum is σ = 482678508. Its totient is φ = 70349472.

The previous prime is 216911531. The next prime is 216911567. The reversal of 216911538 is 835119612.

It can be written as a sum of positive squares in 2 ways, for example, as 212488929 + 4422609 = 14577^2 + 2103^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (216911531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162181 + ... + 163512.

Almost surely, 2^216911538 is an apocalyptic number.

216911538 is an abundant number, since it is smaller than the sum of its proper divisors (265766970).

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

216911538 is a wasteful number, since it uses less digits than its factorization.

216911538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325738 (or 325735 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 216911538 is about 14727.9169606567. The cubic root of 216911538 is about 600.8428321689.

The spelling of 216911538 in words is "two hundred sixteen million, nine hundred eleven thousand, five hundred thirty-eight".