21116181 has 8 divisors (see below), whose sum is σ = 28551744. Its totient is φ = 13879040.

The previous prime is 21116119. The next prime is 21116191. The reversal of 21116181 is 18161112.

It is a happy number.

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 21116181 - 2²³ = 12727573 is a prime.

It is a super-2 number, since 2×21116181² = 891786200049522, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21116191) 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, 49356 + ... + 49781.

It is an arithmetic number, because the mean of its divisors is an integer number (3568968).

Almost surely, 2^21116181 is an apocalyptic number.

It is an amenable number.

21116181 is a deficient number, since it is larger than the sum of its proper divisors (7435563).

21116181 is an equidigital number, since it uses as much as digits as its factorization.

21116181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99211.

The product of its digits is 96, while the sum is 21.

The square root of 21116181 is about 4595.2345968405. The cubic root of 21116181 is about 276.4002672704.

Adding to 21116181 its reverse (18161112), we get a palindrome (39277293).

The spelling of 21116181 in words is "twenty-one million, one hundred sixteen thousand, one hundred eighty-one".