21041507 has 4 divisors (see below), whose sum is σ = 21170760. Its totient is φ = 20912256.

The previous prime is 21041479. The next prime is 21041513. The reversal of 21041507 is 70514012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21041507 - 2¹² = 21037411 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21041107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64382 + ... + 64707.

It is an arithmetic number, because the mean of its divisors is an integer number (5292690).

Almost surely, 2^21041507 is an apocalyptic number.

21041507 is a deficient number, since it is larger than the sum of its proper divisors (129253).

21041507 is a wasteful number, since it uses less digits than its factorization.

21041507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129252.

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

The square root of 21041507 is about 4587.1022443368. The cubic root of 21041507 is about 276.0740673231.

Adding to 21041507 its reverse (70514012), we get a palindrome (91555519).

The spelling of 21041507 in words is "twenty-one million, forty-one thousand, five hundred seven".