20689121 has 8 divisors (see below), whose sum is σ = 22285824. Its totient is φ = 19150560.

The previous prime is 20689111. The next prime is 20689139. The reversal of 20689121 is 12198602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20689121 - 2¹⁰ = 20688097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20689111) 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, 13796 + ... + 15221.

It is an arithmetic number, because the mean of its divisors is an integer number (2785728).

Almost surely, 2^20689121 is an apocalyptic number.

It is an amenable number.

20689121 is a deficient number, since it is larger than the sum of its proper divisors (1596703).

20689121 is a wasteful number, since it uses less digits than its factorization.

20689121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29071.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 20689121 is about 4548.5295426104. The cubic root of 20689121 is about 274.5242285928.

The spelling of 20689121 in words is "twenty million, six hundred eighty-nine thousand, one hundred twenty-one".