21813117 has 8 divisors (see below), whose sum is σ = 29494080. Its totient is φ = 14337120.

The previous prime is 21813101. The next prime is 21813163. The reversal of 21813117 is 71131812.

It is a happy number.

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

It is not a de Polignac number, because 21813117 - 2⁴ = 21813101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813817) 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, 50992 + ... + 51417.

It is an arithmetic number, because the mean of its divisors is an integer number (3686760).

Almost surely, 2^21813117 is an apocalyptic number.

It is an amenable number.

21813117 is a deficient number, since it is larger than the sum of its proper divisors (7680963).

21813117 is a wasteful number, since it uses less digits than its factorization.

21813117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102483.

The product of its digits is 336, while the sum is 24.

The square root of 21813117 is about 4670.4514771058. The cubic root of 21813117 is about 279.4082613833.

Adding to 21813117 its reverse (71131812), we get a palindrome (92944929).

The spelling of 21813117 in words is "twenty-one million, eight hundred thirteen thousand, one hundred seventeen".