20021709 has 8 divisors (see below), whose sum is σ = 27148320. Its totient is φ = 13121456.

The previous prime is 20021693. The next prime is 20021711. The reversal of 20021709 is 90712002.

It is a happy number.

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 20021709 - 2⁴ = 20021693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021759) 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, 56382 + ... + 56735.

It is an arithmetic number, because the mean of its divisors is an integer number (3393540).

Almost surely, 2^20021709 is an apocalyptic number.

It is an amenable number.

20021709 is a deficient number, since it is larger than the sum of its proper divisors (7126611).

20021709 is a wasteful number, since it uses less digits than its factorization.

20021709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113179.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 20021709 is about 4474.5624367082. The cubic root of 20021709 is about 271.5399382995.

The spelling of 20021709 in words is "twenty million, twenty-one thousand, seven hundred nine".