21221017 has 8 divisors (see below), whose sum is σ = 22260096. Its totient is φ = 20206512.

The previous prime is 21221003. The next prime is 21221021. The reversal of 21221017 is 71012212.

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 21221017 - 2¹⁹ = 20696729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4363 + ... + 7840.

It is an arithmetic number, because the mean of its divisors is an integer number (2782512).

Almost surely, 2^21221017 is an apocalyptic number.

It is an amenable number.

21221017 is a deficient number, since it is larger than the sum of its proper divisors (1039079).

21221017 is a wasteful number, since it uses less digits than its factorization.

21221017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12287.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21221017 is about 4606.6275082754. The cubic root of 21221017 is about 276.8569293358.

Adding to 21221017 its reverse (71012212), we get a palindrome (92233229).

The spelling of 21221017 in words is "twenty-one million, two hundred twenty-one thousand, seventeen".