21507041 has 8 divisors (see below), whose sum is σ = 22025064. Its totient is φ = 20995200.

The previous prime is 21507007. The next prime is 21507071. The reversal of 21507041 is 14070512.

It can be written as a sum of positive squares in 4 ways, for example, as 16974400 + 4532641 = 4120^2 + 2129^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21507041 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21507071) 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 7 ways as a sum of consecutive naturals, for example, 5915 + ... + 8831.

It is an arithmetic number, because the mean of its divisors is an integer number (2753133).

Almost surely, 2^21507041 is an apocalyptic number.

It is an amenable number.

21507041 is a deficient number, since it is larger than the sum of its proper divisors (518023).

21507041 is a wasteful number, since it uses less digits than its factorization.

21507041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3091.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21507041 is about 4637.5684361527. The cubic root of 21507041 is about 278.0952393523.

Adding to 21507041 its reverse (14070512), we get a palindrome (35577553).

Subtracting from 21507041 its reverse (14070512), we obtain a square (7436529 = 2727²).

The spelling of 21507041 in words is "twenty-one million, five hundred seven thousand, forty-one".