21141817 has 4 divisors (see below), whose sum is σ = 21308416. Its totient is φ = 20975220.

The previous prime is 21141803. The next prime is 21141821. The reversal of 21141817 is 71814112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21141817 is a prime.

It is a super-2 number, since 2×21141817² = 893952852122978, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21141791 and 21141800.

It is not an unprimeable number, because it can be changed into a prime (21141877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83109 + ... + 83362.

It is an arithmetic number, because the mean of its divisors is an integer number (5327104).

Almost surely, 2^21141817 is an apocalyptic number.

It is an amenable number.

21141817 is a deficient number, since it is larger than the sum of its proper divisors (166599).

21141817 is a wasteful number, since it uses less digits than its factorization.

21141817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166598.

The product of its digits is 448, while the sum is 25.

The square root of 21141817 is about 4598.0231621861. The cubic root of 21141817 is about 276.5120761828.

Adding to 21141817 its reverse (71814112), we get a palindrome (92955929).

The spelling of 21141817 in words is "twenty-one million, one hundred forty-one thousand, eight hundred seventeen".