216117261 has 32 divisors (see below), whose sum is σ = 325987200. Its totient is φ = 141488640.

The previous prime is 216117247. The next prime is 216117271. The reversal of 216117261 is 162711612.

It is a happy number.

216117261 is a `hidden beast` number, since 21 + 611 + 7 + 26 + 1 = 666.

It is not a de Polignac number, because 216117261 - 2⁶ = 216117197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216117221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 468571 + ... + 469031.

It is an arithmetic number, because the mean of its divisors is an integer number (10187100).

Almost surely, 2^216117261 is an apocalyptic number.

It is an amenable number.

216117261 is a deficient number, since it is larger than the sum of its proper divisors (109869939).

216117261 is a wasteful number, since it uses less digits than its factorization.

216117261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746 (or 740 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 216117261 is about 14700.9272156555. The cubic root of 216117261 is about 600.1085553584.

Adding to 216117261 its reverse (162711612), we get a palindrome (378828873).

The spelling of 216117261 in words is "two hundred sixteen million, one hundred seventeen thousand, two hundred sixty-one".