21717069 has 16 divisors (see below), whose sum is σ = 31756800. Its totient is φ = 13091760.

The previous prime is 21717067. The next prime is 21717071. The reversal of 21717069 is 96071712.

It is an interprime number because it is at equal distance from previous prime (21717067) and next prime (21717071).

It is not a de Polignac number, because 21717069 - 2¹ = 21717067 is a prime.

It is a super-2 number, since 2×21717069² = 943262171901522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21717061) 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 15 ways as a sum of consecutive naturals, for example, 4914 + ... + 8220.

It is an arithmetic number, because the mean of its divisors is an integer number (1984800).

Almost surely, 2^21717069 is an apocalyptic number.

It is an amenable number.

21717069 is a deficient number, since it is larger than the sum of its proper divisors (10039731).

21717069 is a wasteful number, since it uses less digits than its factorization.

21717069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3520.

The product of its (nonzero) digits is 5292, while the sum is 33.

The square root of 21717069 is about 4660.1576153602. The cubic root of 21717069 is about 278.9975591056.

The spelling of 21717069 in words is "twenty-one million, seven hundred seventeen thousand, sixty-nine".