216911631 has 8 divisors (see below), whose sum is σ = 289445040. Its totient is φ = 144492992.

The previous prime is 216911579. The next prime is 216911641. The reversal of 216911631 is 136119612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216911631 - 2⁶ = 216911567 is a prime.

It is a super-2 number, since 2×216911631² = 94101311326160322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216911641) 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, 24180 + ... + 31913.

It is an arithmetic number, because the mean of its divisors is an integer number (36180630).

Almost surely, 2^216911631 is an apocalyptic number.

216911631 is a deficient number, since it is larger than the sum of its proper divisors (72533409).

216911631 is a wasteful number, since it uses less digits than its factorization.

216911631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57385.

The product of its digits is 1944, while the sum is 30.

The square root of 216911631 is about 14727.9201179257. The cubic root of 216911631 is about 600.8429180385.

The spelling of 216911631 in words is "two hundred sixteen million, nine hundred eleven thousand, six hundred thirty-one".