21017006 has 4 divisors (see below), whose sum is σ = 31525512. Its totient is φ = 10508502.

The previous prime is 21016997. The next prime is 21017027. The reversal of 21017006 is 60071012.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5254250 + ... + 5254253.

It is an arithmetic number, because the mean of its divisors is an integer number (7881378).

Almost surely, 2^21017006 is an apocalyptic number.

21017006 is a deficient number, since it is larger than the sum of its proper divisors (10508506).

21017006 is a wasteful number, since it uses less digits than its factorization.

21017006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10508505.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21017006 is about 4584.4308261768. The cubic root of 21017006 is about 275.9668709798.

Adding to 21017006 its reverse (60071012), we get a palindrome (81088018).

The spelling of 21017006 in words is "twenty-one million, seventeen thousand, six".