21518041 has 8 divisors (see below), whose sum is σ = 22771584. Its totient is φ = 20291040.

The previous prime is 21518033. The next prime is 21518047. The reversal of 21518041 is 14081512.

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 21518041 - 2³ = 21518033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21518047) 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, 4956 + ... + 8221.

It is an arithmetic number, because the mean of its divisors is an integer number (2846448).

Almost surely, 2^21518041 is an apocalyptic number.

It is an amenable number.

21518041 is a deficient number, since it is larger than the sum of its proper divisors (1253543).

21518041 is a wasteful number, since it uses less digits than its factorization.

21518041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13271.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21518041 is about 4638.7542508738. The cubic root of 21518041 is about 278.1426428399.

Adding to 21518041 its reverse (14081512), we get a palindrome (35599553).

Subtracting from 21518041 its reverse (14081512), we obtain a square (7436529 = 2727²).

The spelling of 21518041 in words is "twenty-one million, five hundred eighteen thousand, forty-one".