21718041 has 4 divisors (see below), whose sum is σ = 28957392. Its totient is φ = 14478692.

The previous prime is 21718033. The next prime is 21718043. The reversal of 21718041 is 14081712.

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 not a de Polignac number, because 21718041 - 2³ = 21718033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21718043) 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, 3619671 + ... + 3619676.

It is an arithmetic number, because the mean of its divisors is an integer number (7239348).

Almost surely, 2^21718041 is an apocalyptic number.

It is an amenable number.

21718041 is a deficient number, since it is larger than the sum of its proper divisors (7239351).

21718041 is an equidigital number, since it uses as much as digits as its factorization.

21718041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7239350.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 21718041 is about 4660.2619025115. The cubic root of 21718041 is about 279.0017214472.

Adding to 21718041 its reverse (14081712), we get a palindrome (35799753).

The spelling of 21718041 in words is "twenty-one million, seven hundred eighteen thousand, forty-one".