216639941 has 16 divisors (see below), whose sum is σ = 255104640. Its totient is φ = 180107520.

The previous prime is 216639937. The next prime is 216639953. The reversal of 216639941 is 149936612.

It is a cyclic number.

It is not a de Polignac number, because 216639941 - 2² = 216639937 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216639901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49265 + ... + 53481.

It is an arithmetic number, because the mean of its divisors is an integer number (15944040).

Almost surely, 2^216639941 is an apocalyptic number.

It is an amenable number.

216639941 is a deficient number, since it is larger than the sum of its proper divisors (38464699).

216639941 is a wasteful number, since it uses less digits than its factorization.

216639941 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4444.

The product of its digits is 69984, while the sum is 41.

The square root of 216639941 is about 14718.6935901254. The cubic root of 216639941 is about 600.5919537555.

The spelling of 216639941 in words is "two hundred sixteen million, six hundred thirty-nine thousand, nine hundred forty-one".